trackways

August 19, 2000 - The BPS Track Meet

General

On August 19, the Birmingham Paleontological Society (BPS), the Alabama Museum of Natural History, and the Geological Survey of Alabama will hold an all day session in Smith Hall at the University of Alabama to photograph and label Pennsylvanian age trackways collected from the Union Chapel Mine in Walker County, Alabama. The Alabama Museum of Natural History will host the event and provide refreshments and lunch to everyone involved. Persons with tracks/trackways are asked to arrive at Smith Hall around 9:00 am to begin set up for photographing and labeling. The photography, specimen labeling, and data recording will last until around 5 pm Saturday afternoon. From 11:00 to 12 noon, there will be a break for a series of short talks that will address the group on the geology of the Union Chapel Mine and the significance of collecting these Paleozoic trackways.

This "Track Meet" is a unique opportunity to document most of the trackways that have been taken from the Union Chapel Mine, collected mainly during the year 2000. The purpose of this session is:

To compile a photographic record of the Union Chapel Mine trackways,

To document the owners of tracks/trackways in the event a researcher needs to study these specimens in the future. A photographic catalogue is planned for the publication of this data and will be titled BPS Monograph # 1.

To permanently label all specimens collected at the Union Chapel Mine. These labels will be affixed to the back side of the specimen, not interfering with the track/trackway.

It is requested that people bring only tracks/trackways from the Union Chapel Mine for the August 19 Track Meet. Also, plant fossils from the Union Chapel Mine should not be brought to be photographed at this session. There will a separate photo session for plant fossils collected at the Union Chapel Mine. Likewise, trackways from other Alabama locations collected by the BPS would also be the subject of a future photo session.

It is also requested that each specimen brought to the Track Meet for photography be thoroughly cleaned before unloading the specimen at the registration table. This cleaning should be done by the specimen(s) owner before arriving at Smith Hall. If calcite scale is present, a bit of vinegar poured onto the shale for 10-15 seconds may remove some of it, if the vinegar is gently worked over the surface with a soft toothbrush. Be extremely gentle with the specimen because vigorous scrubbing the specimen with water/vinegar will destroy the track/trackway.

Agenda

9 am to 11:00 am: Registration, triage, preparation of permanent labels, photography

11:00 am to 12:00 noon: Speakers

Ed Hooks, Alabama Museum of Natural History:

Welcome

The Importance of the Amateur Paleontologist

BPS Display Case

Kathy Twieg:

Address from the President to the Birmingham Paleontological Society

BPS Monograph Series

Andrew K. Rindsberg, Geological Survey of Alabama:

Donation of Pennsylvanian Trackways to Geological Survey of Alabama for their Educational Outreach Program and Permanent Collection; Ethics in Collecting, Trading, and Selling Fossils

Jack Pashin, Geological Survey of Alabama:

Geology of the Pottsville Formation and its relation the Union Chapel Mine

12:00 noon to 1:00 p.m.: Lunch (provided by BPS)

1:00 p.m. to 5:00 p.m.: Photography and preparation of permanent labels

Registration, Triage, and BPS Data Base

Upon arriving at Smith Hall at the beginning of the Track Meet Saturday morning, each person will be greeted at the registration desk set up outside the front of Smith Hall. Labeling and filling out data base forms will also be done outside the front of Smith Hall. In the event of inclement weather, registration, triage, data base work, and labeling will all take place inside Smith Hall, on the 1st floor. Volunteers will be available to help specimen owners unload and carry specimens to Smith Hall from the parking area. If a person has specimens for the photo shoot, the person should be registered by a BPS host at the front table. Upon signing in, the person will present his/her specimens to be photographed. Andy Rindsberg, Geological Survey of Alabama, will evaluate each sample for photography priority. Those track/trackway specimens of the highest quality will be given a red dot and receive first priority for the photo shoot. The second quality tracks/trackways will be given a blue dot and will be photographed later if time allows in the afternoon. Specimens of minor value to this effort will be given a green dot, and if the owner prefers, may be donated to the Geological Survey of Alabama for their educational outreach program. A depot for such specimens will be marked. Conversely, there will be trackways that the Alabama Museum of Natural History or Geological Survey of Alabama consider of high value to scientific research. If this is the case, Andy will place a yellow dot on the specimen and request donation of the specimen to the Museum or Survey for their permanent collections, again, at the discretion of the owner. In addition, Ed Hooks (Alabama Museum of Natural History) will request that several of the most important trackways be displayed in the BPS display case in Smith Hall for a 4-6 month duration, after which time the specimens will be returned to their owners. These specimens will also receive a yellow dot.

Once Andy Rindsberg has graded track/trackway specimens with red, blue, or green dots, a Track Meet volunteer will give the owner of the specimen(s) to be photographed a series of unique numbers, one number for each rock specimen. Next, the volunteer will give the owner a data sheet on which the owner shall list the necessary data for each track/trackway. The information on this data sheet will be:

Collector’s name

Taxon (ichnogenus and ichnospecies, if known)

Date collected (month/year)

Location collected (Union Chapel Mine)

County location (Walker County, Alabama)

Geologic formation (Pottsville Formation)

Geologic Age(Pennsylvanian)

Unique sample number (e.g. UCM –1)

All that the specimen owner needs to write on the data sheet(s) are: his/her name, specimen name, and date collected. These data sheets will be pre-printed with the standard site information (categories d-h).

Labeling

After the data sheet has been filled out, the owner with the assistance of a Track Meet volunter, will move the track/trackway specimens to a table where permanent labels are being attached to the rock. The rock will be turned over and a permanent label will be affixed to the back side of the rock by a Track Meet volunteer. This label will be a postage stamp-sized white label, and another volunteer will take the data sheet and print the necessary information on the permanent label on the rock with a black indelible pen. The permanent label on the rock should read:

Unique sample number

Taxon (ichnogenus and ichnospecies, if known)

Date collected

Location collected

County location

Finally, the volunteer will give the owner a temporary label to be attached to the specimen with two way cellophane tape. All that is written on the temporary label is the specimen’s unique sample number within the range of UNC-001 to UNC-500. This temporary label will be attached to the specimen for the photograph; after which it may be discarded. However, it is critical that this paper label stay attached to the rock specimen until after the track/trackway is photographed.

Transport of Specimens to the 2^nd Floor for Photography and Data Input

Another Track Meet volunteer will assist the owner in transporting the specimens to the 2^nd floor of Smith Hall for photographing. There are two large classrooms on the 2^nd floor of Smith Hall where the specimens, in their boxes, must be staged prior to the photo shoot. In one classroom, a camera table and artificial lighting have been arranged for the photo session. Once the specimens have been photographed, the owner will place the specimens back in the staging area and attach a "post-it" to the specimen box indicating that photographs have been taken.

In another classroom where the specimens will also be also staged, Prescott Atkinson will be using a computer to input information about the samples into the BPS database.

The owner will take the data sheet to Prescott to enter specimen data in the database. Track Meet volunteers will assist in transporting the rock specimens downstairs and back to the owner’s vehicles, after the photo session and data input are finished.

There will probably be many tracks that will not brought to the August 19 "track meet". The labeling session at the "track meet" should demonstrate to everyone the importance of labeling the Union Chapel Mine specimens and how everyone should label their additional specimens not brought to the August 19 Track Meet.

Photo Session

Ricky Yanaura, Staff Photographer for the University of Alabama, has provided technical assistance to the Alabama Museum of Natural History and the BPS on how to best photograph the track/trackway specimens. He recommends using 35 mm print film, in a camera mounted on a tripod in a large classroom on the second floor of Smith Hall. A camera table will be positioned in one corner of the classroom and serve as a stationary base to place the rock specimens for photography. The camera can be raised or lowered depending on the size of the specimen. Ricky will supply all artificial lighting and a series of lighting reflectors to capture the best possible lighting contrast for the rock specimen. The Alabama Museum of Natural History will furnish all the film and pay for the film developing. Ron Buta will be the photographer for the track meet and will use a Nikon 35 mm camera with a macro lens. Ron will have a volunteer to assist him throughout the entire photo session. Ron and Ricky will get together a few days in advance to practice a dry run for the lighting and camera table set up on the second floor of Smith Hall.

Each specimen may be lightly sprayed with water before the photo shoot to enhance rock contrast in order to see the track/trackway more clearly. A metric bar scale will be placed next to each specimen for each photograph. The temporary label shall be arranged properly on the rock specimen for the photo shoot.

Others are welcome to also photograph track/trackway specimens with their own cameras/digital cameras while the specimens are being photographed for the BPS Monograph by Ron Buta.

Security

Security will be provided by volunteers to ensure that the general public does not enter the museum while the museum is closed. In addition, the BPS will provide volunteers to ensure the security of all track/trackway specimens during the August 19 Track Meet.

Media

The Alabama Museum of Natural History has invited the local media to cover the August 19 Track Meet.

Volunteers

Currently, 13 persons have volunteered to work all day at the Track Meet. Twelve volunteers are needed at a very minimum to operate this event. Anyone who would like to help with the Track Meet is strongly encouraged to volunteer. The BPS and the museum would really appreciate it.

Housekeeping

Two Track Meet volunteers will assist to ensure that the building and grounds of Smith Hall are properly policed for debris, trash, and disposable lunch and refreshment materials. This will be most important if it rains and registration, triage, and labeling have be done inside Smith Hall. These volunteers will also assist with serving lunch.

Lunch, Refreshments

Coffee, drinks, and pastries will be served during the day. Lunch will consist of chicken/sausage gumbo, rice, French bread, and a touch of filé. There will be no charge for lunch or refreshments.

May 28, 2000 - Pennsylvanian Fossils, Walker Co, AL

This collecting site continues to be popular with the BPS, today’s field trip being the third organized visit in only four months. There were good reasons for returning to the site at this time. First, it is still rich in amphibian tracks and plant fossils, in spite of the many people visiting the site during the past four months. Second, we were informed by the owner of the mine that reclamation of the Union Chapel Mine would begin in late May, and that this may enhance our ability to find new and interesting material that had been previously buried in the rock piles. However, the reclamation effort has been stalled for a variety of reasons, and I have heard that full-scale reclamation might not start until August. Nevertheless, the unmoved piles still yield good specimens, and it is still possible to find good quality tracks lying exposed in spite of the many visits people have made to the mine. Sometimes pieces are missed because of a poor Sun angle or because people are tired when they pass an area and simply don’t notice a track specimen.

I felt like I had a "good day" today for track and plant fossils from this site. The first picture shows a fine set of amphibian tracks with at least four toes. Note how the size of the tracks alternate, as if the hind and forefeet have different sizes.
	Fig. 1 - Small amphibian tracks with at least four toes. The tracks resemble those of the genus Cincosaurus cobbi in Museum Paper No. 9, by Aldrich and Jones (1930). However, the tracks here are much smaller than those illustrated in their article.

The second picture shows tracks of a somewhat different creature, again with at least four toes and possible evidence of a pad.
	Fig. 2 - Another set of small tracks with four toes and evidence for a pad.

The third and fourth pictures show a fine set of tracks whose visibility depends on the Sun angle when dry. I noticed these tracks after splitting a rock. The two halves, giving direct and inverse impressions, were wet and the tracks obvious. However, after the pieces dried in the back of my truck, I could not see the tracks! This set is interesting because it looks like the creature was walking around an obstacle of some some sort.

Fig. 3 - A small set of tracks where the creature apparently walked around an obstacle of unknown nature. This set also resembles Cincosaurus cobbi, but are nuch smaller than the ones illustrated in Aldrich and Jones 1930.


	Fig. 4 - Close up of part of the tracks in the previous picture.

The fifth picture shows a definite trace fossil that is likely connected to a fish. The picture shows two doubled sine waves, and at least one wave has four peaks on the whole rock. The sine waves could be due to fins scraping the bottom, and perhaps two fish made these tracks, each with a pair of fins touching the mud.
	Fig. 5 - Possible trace fossils of fish fins swishing along bottom of shallow water or swampy area.

The sixth picture shows an interesting trunk cast of a small tree. I had a hard hat on this visit, and felt emboldened to go a little closer to the high wall than I had been before. I found this stunning small trunk near but not exactly at the wall. I call this the "Devil’s Tower" specimen because it strongly resembles Devil’s Tower in Wyoming. The black verticle bands represent carbonized plant material, and I suspect the tree was a species of Sigillaria. Since it tapers a little, I also suspect the piece was near the bottom of the trunk.

Fig. 6 - The "Devil’s Tower" specimen, a trunk cast of small lycopod, probably of the genus Sigillaria.

The seventh picture shows a variety of typical bark impressions and a small cast of a Calamites pith I found on this day. The bark impressions are of the genus Lepidophloios, by far the most abundant type at this site. This is in great contrast to the Warrior construction site (see BPS field trip report for March 27, 1999), where hundreds of bark impressions of Lepidodendron have been found, but no definite pieces of Lepidophloios.

Fig. 7 - Various bark impressions of Lepidophloios and a Calamites medullary cast fossil

Other Track Impressions
	Fig. 8 - A medium sized set of a few tracks, likely to be Cincosaurus jonesii (Aldrich and Jones 1930).

The final pictures I show are of a few tracks found on different days but which have not been shown in previous reports.
	Fig. 9 - A small set of tracks with three clear toes, probably of the genus Cincosaurus.

Fig. 10 - Small tracks of unknown creature, from part of a much larger slab with 3 or 4 criss-crossing tracks. Each track is less than a penny in size.

Fig. 11 - This piece shows two different sets of tracks, one larger set going left, and a smaller set going right. The two sets overlap, giving a confusing pattern of overlapping prints.

Fig. 12 - This piece includes tracks of probably one of the same two creatures in Figure 11.

Alabama

Pennsylvanian

trackways

March 19, 2000 - Pennsylvanian Fossils, Walker Co, AL

Department of Physics and Astronomy
University of Alabama
Tuscaloosa, Alabama

It was decided at the March meeting that the BPS should return to this mine once again as an organized field trip. As I have noted in previous reports, this is a site the BPS visited with great success just two months earlier. The site is rich in footprint fossils of Pennsylvanian amphibians and other creatures. Although the previous organized visit, on January 23, occurred on a rather bleak day, it was nothing like the one today. Rain fell hard all day across most of Alabama and never let up even for a few minutes. Because of the weather, only six people turned up for this outing.

Figure 1 Unusual tracks of one or two large creatures that must have been moving in very wet mud.

In spite of the weather, several of us still found nice tracks and other fossils. I show a few that I picked up here. One large set of tracks I found was lying at the bottom of a rock pile that had been thoroughly searched. After the tracks were cleaned of mud, it looks to me like they are amphibian tracks that were laid down in rather wet mud. The impressions are wide as the creatures' whole body probably sloshed in the mud. There are two sets of tracks on the main piece, and details of one are shown in the close-up.

Figure 2 Close-up of part of the previous specimen, showing likely toe prints flanking the broad body scrape.

Figure 3 Small tracks of one or more creatures that could be Bipedes aspodon.

A much smaller set of tracks I found in a different area has small y-shaped prints in a bit of a random pattern. In Museum Paper No. 9 of the Alabama Museum of Natural History (authors Aldrich and Jones), a creature that produced similar tracks is known as Bipedes aspodon. At least two sets of tracks are also present on this piece. Bipedes aspodon is described by Aldrich and Jones as an animal with only two toes. Although Aldrich and Jones clearly considered the creature to be an amphibian, BPS members who found similar tracks felt they are more likely to be tracks of an arthropod.

Figure 4 Single print of Quadropedia prima, a modest-sized amphibian. At this layer, the track shows five clear toes as well as a pad.

I found some other interesting and larger tracks on a large rock on the well-searched rock piles. I suspected tracks might be inside at a deeper level in this rock. The rock had interesting deposits or formations that covered different layers, but it was not clear what these features might be. After removing many layers of the rock, I did indeed find four footprints of a modest-sized creature which, according to Museum Paper No. 9, is an amphibian known as Quadropedia prima. Aldrich and Jones state that the creature is higher in the scale than most of the species they illustrated in their article, because it walked more like later reptiles. They point out the presence of a distinct pad, which we can see in the pictures I show here. The four prints could be detected at several different layers, and at least one of the prints was well-defined at all of the layers. The appearance of the prints seemed different at different layers, suggesting that some of the variety in the prints we have been finding at the site is due in part to the different layers that were exposed.

Figure 5 Two tracks of the same creature, the one at right being the same foot as in the previous picture, but the print looks different because it is at a different level. At this level, only three toes are seen, with a strong pad.

Other Notes on the Union Chapel Site January 23-March 19, 2000

The Union Chapel Mine was visited many times by BPS members and guests between January 23 and March 19. Ashley Allen brought to the February BPS meeting a huge rock with a set of excellent large amphibian prints. Bruce Relihan brought to the March BPS meeting a large stump cast of a likely Lepidodendron. The stump is more than a foot in diameter and tapers around the edges, as if it were near the bottom of the original trunk. Bruce related the heroic effort he put into getting the huge fossil by himself, which involved building a rock ramp to allow him to get it into his truck. Steve Minkin also brought to the last BPS meeting an excellent set of modest-sized tracks found by his wife.

All in all, the Union Chapel site elicited such great interest and finds that Steve Minkin asked Ed Hooks if the BPS could have a temporary display case at the Alabama Museum of Natural History in Tuscaloosa. Ed agreed to this and some of the new Union Chapel pieces may soon be on display for the public to see!

January 23, 2000 - Pennsylvanian Fossils, Walker Co, AL

On this first field trip of the first year of the new millennium (or the last year of the old millennium), the BPS had the pleasure of visiting a truly interesting surface mine in Walker County. The Union Chapel Mine is smaller than the Cedrum Mine we visited last month, but is located in the same general area. The field trip was attended by 11 "diehards" who were not put off by the weather, which started out rainy and cold. By the time we arrived at the site (about 9am), the rain had completely subsided and we were virtually rain-free the whole time we were there. However, the clouds persisted and the day was a little gloomy.

Fig. 1 - Group at the site conferring about finds.

The trip was arranged by Ashley Allen, who heard about the site through his science class. The site proved particularly rich in tracks of amphibians and probably arthropods from the lower Pennsylvanian subdivsion of the Carboniferous Period. The tracks are trace fossils of the footprints of the creatures, and it is clear from the variety of tracks we all found that many different species of creatures are represented. According to Jim Lacefield, track fossils are found at most of the lower Pennsylvanian sites in Alabama, but often they are not as obvious or as richly abundant and diverse as they are at Union Chapel Mine. Like Cedrum and other Pennsylvanian sites the BPS has visited the past year, Union Chapel Mine is also rich in plant fossils. Jim has told me that the mix of other fossils with the usual plants reflects more the environmental differences between sites, rather than significant age differences.

Fig. 2 - One of the rock piles at the site that was rich in tracks.

The following pictures show a few of the track fossils found. These range from some fairly large tracks (a few centimeters per print) to smaller prints that look like Chinese characters, and finally to really small prints that are at most a couple of millimeters or less in size. Some tracks also included obvious tail dragging marks. These can straight or curved, and I recall that Ashley found a particularly wavy specimen. Virtually everyone who was there found one or more interesting track fossils.

Fig. 3 - Excellent amphibian tracks held by Matthew Valente.

Fig. 4 - Tracks resembling Chinese characters.

Fig. 5 - Two sets of small tracks, with likely tail dragging marks.

Fig. 6 - Inverse tracks of unknown creature.

Probably the most spectacular prints from the site were a huge set found by Jim Lacefield, the "likes of which I had never seen", according to Jim. Jim relates the following:

"The handprints, which include long, curving toes with easily-distinguished pads on the tips, are nearly as big as my own. This was a huge beast. Although I had read that some amphibians reached rather large size in the Pennsylvanian, in all my collecting in Coal Age rocks I have never seen any that were anywhere nearly this large." A digital photo of Jim's specimen is shown here.

Fig. 7 - Monster tracks found by Jim Lacefield, in an image prepared for inclusion in his book.

Fig. 8 - Stunning and unusual branch cast of a species of Sigillaria, probably S. elegans according to Plant Fossils of West Virginia by Gillespie et al. 1978.

Although the track fossils were superb, and were the principal things we all searched for, the plant fossils were also quite impressive and ranked as my favorites. Bark impressions of Lepidophloios, a subgenus of the Lepidodendrales, were especially abundant at this site. Jim Lacefield was seeing so much Lepidophloios that he was wondering if there was any Lepidodendron. However, both Sigillaria and Lepidodendron were well represented at the site. I show specimens of Sigillaria and a genus related to Lepidodendron here.

By far the most beautiful of any specimens I have seen, at Union Chapel or any other site, were the compressed cast fossils of two branches of a Sigillaria species. The leaf scars are small hexagons with a central spot, and are so well-preserved that even fine ridge-like details are seen. I spent 45 minutes hammering on a large rock to get pieces of these branches out. On the same rock was an especially beautiful species that looks at first like a Lepidodendron, with pieces of highly compressed cast fossils lying about. According to Jim Lacefield, this might be a representative of a related genus called Diaphorodendron.

Fig. 9 - Close-up of Sigillaria specimen

Fig. 10 - Bark impression of a likely Diaphorodendron, a genus related to Lepidodendron.

Other items of interest were a snail fossil found by Kathy Twieg, a large Lepidophloios cast found by Ashley Allen, a rhizome of Calamites by Jim Lacefield, myself, and others, a small medullary cast of Calamites found by Bruce Relihan, and a gigantic lycopod stump (probably weighing more than 800 pounds) noticed by Jim Lacefield Jim also showed me a likely trace fossil of a hermit crab and also tiny insect prints. Concerning the rhizome of Calamites, Jim gave me the following comments: "Calamites, like all horsetails, propogates vegetatively through spreading by underground stems called rhizomes. New Calamites stems sprout upward from these horizontal, underground stems. It's a type of asexual reproduction that allows them to spread quickly into new territory and also anchors them firmly in the unstable ground along rivers and out onto newly deposited delta sediments. Those round structures were clusters of cells that, under the right conditions, could develop into new Calamites shoots. The rhizomes of Calamites look quite similar to the stems in most cases, but have nodes that get progressively closer together as they get out approach the apical area (the growth tip that spreads outward through the soil.

	Fig. 11 - Part of a rhizome of Calamites , showing characteristic round features that are not normally seen on calamites branch casts.

Fig. 12 - Huge stump cast fossil, probably 800 pounds in weight, probably of a lycopod.

There is no question that Union Chapel Mine has been one of the most interesting fossil sites that the BPS has had the privilege of visiting. According to Ashley, the Union Chapel Site will be reclaimed very soon. Since our original visit, various subgroups of BPS members have been back to the site, trying to salvage as many tracks and other items as possible before the site is gone.

Additional Pictures from Union Chapel Mine

The following pictures provide more examples of the types of fossils found at the Union Chapel Mine. In the two weeks after the January 23 field trip, several of us returned to the site. These are some of the items found on these return trips.

Fig. 1 - Stump cast of a Lepidophloios arborescent lycopod. Jim Lacefield and I were exploring one of the popular track rock piles at the site, and he pointed out this excellent stump cast to me. The piece weighs close to 300 lbs, but fortunately it lay on a slope that was accessible by my truck. All one could do is move the thing downhill. I rolled it down about 25 feet of slope onto a dirt embankment, and then with help moved it into my truck. It is pictured in my backyard garden area.

Fig. 2 - this is a different view of the same stump cast, showing the large indentation that seems to characterize the shape of the trunks of these trees. In the January 23 report, I show a picture of an 800 lb stump with a similar indentation.

Fig. 3 - this piece shows two criss-crossing tracks from small creatures with no tail-dragging marks.

Fig. 4 - two sets of small tracks with distinct tail-dragging marks.

Fig. 5 - complex inverse tracks of a still different creature, with only a weak tail dragging mark.

Fig. 6 - a single large inverse print of what must have been a massive creature. This could have been a type of Attenosaurus, although the print is really different from those shown in Museum paper No. 9 of the Alabama Museum of Natural History, by Aldrich and Jones, published in 1930.

Fig. 7 - excellent set of small inverse prints with a weak tail-dragging mark.

Fig. 8 - another lycopod stump, this time covered with excellent leaf scars on side facing camera. Weighs about 200 lbs

Fig. 9 - three sets of small prints, found on a "page" of a vertically standing rock that opened into many layers.

Fig. 10 - a set of tracks, nearly 2 feet long, found by Jim Lacefield. Jim believes these are fossil tracks of a horseshoe crab. The actual crabs were not in the original photo!

Fig. 11 - Jim also found this rock with excellent fossils of lycopod branches. Details are present at various levels and the branching is complex.

Walker

Alabama

trackways

November 20, 1999 - Bibb Co, AL

This Saturday field trip was the first visit even by veteran BPS members to a quarry located in north Bibb County. The rocks from this quarry have been used as rip-rap at several highway locations, the best ones I know of being on a ramp at Exit 79 and between Exits 77 and 79 on I20/59 near Tuscaloosa.

	Fig. 1 - View of quarry area with small lake surrounded by steep cut walls

The trip was attended by 20-25 BPS members and guests on the first rainy day we had in nearly three weeks.

This quarry is a largely abandoned location where rocks of middle Ordovician age (460-480 million years) have been exposed. The rock formations at this site are part of the well known Chickamauga Limestone Group. The main quarry pit is now a small lake filled with deep-looking water having a strong aquamarine color. The lake is surrounded by steep cut cliffs. Rocks are scattered in large piles around a wide area near the lake, and it was among these piles that BPS members searched for fossils of mostly marine animals. In spite of the vastness of the area, it took some tenacity to find fossils since fossiliferous rocks were not that common.

Fig. 2 - Group discussing strategy for exploring the area.



Fig. 3 - View towards rock piles around the lake.

	Fig. 4 - Ordovician brachiopods, probably of the genus Sowerbyella, from a rock pile away from the lake

Apparently, it is the fossils themselves that tell us the age of the rocks at this site. According to Prof. Carl Stock of the University of Alabama Department of Geology, the main index fossils are conodonts, which are very small, sometimes cone-like objects whose nature is not well understood. I am not sure that any of us noticed such fossils, but a magnifier would probably be needed to see them in any case. More obvious index fossils found in quarry rocks are brachiopods. According to R. Wixon (University of Alabama master's thesis, 1984), Ordovician brachiopods are good index fossils because of their abundance worldwide and the short period of their evolutionary timescale. Well-preserved brachiopods of clear middle Ordovician age are found at the quarry and at the I20/59 sites.

	Fig. 5 - From same slab as Fig. 4, showing other kinds of brachiopods on same scale

Many of the brachiopods that we found at the quarry appear to belong to the order Strophomenida which, according to The Fossil Book by Rich, Rich, Fenton, and Fenton (1996), are frequently referred to as "petrified butterflies". There are many genera and species in this order of articulate brachiopods, and I could only identify a few in the rocks that I personally picked up, based on illustrations in Wixon's thesis and Volume H of the Treatise on Invertebrate Paleontology (Moore, editor, 1965). A few are shown in the illustrations here. Larry Hensley found a large slab covered with brachiopod shells mostly about 1 cm in diameter each (see photo). Several of us managed to hammer away at this large rock and get some pieces of it. Many of the brachiopods on this slab appear to be of the genus Sowerbyella.

Fig. 6 - Medium-sized brachiopod, probably of genus Rafinesquina, with smaller Hesperorthis australis brachiopods to upper right and left

Larger brachiopods about 2.5 cm or so in diameter seemed less abundant than the 1cm or smaller pieces. The one I show here, shaped sort of like a tombstone, is probably of the genus Strophomenus or, more likely, Rafinesquina. The largest brachiopod I found is more than 3cm in diameter, and may be of the genus Tetraphalerella, whose members can get this large according to Wixon.

Other fossils found include the stems of crinoids, random stem plates of dis-assembled crinoids, bryozoans, parts of trilobites and, I heard, cystoids. Trace fossils of worm burrows were actually among the easiest fossils to find at this site. A large slab covered with criss-crossing tracks is shown here. Don McDonald also showed me what he thought was the end of a horn coral, and Vicki Lais showed several of us a very large rock having some interesting spiral-shaped fossils that we could not identify. Apparently, someone had previously used a rock saw to cut out a piece of this same rock.

Fig. 7 - large possible Tetraphalerella brachiopod on small rock



Fig. 8 - Intricate worm tracks on face of large slab

Although it was not easy finding fossils at this site, it was clear that everyone who attended the field trip had an enjoyable time. The area was interesting and the rocks mysterious, being older than most of those exposed in regions north and south of the site. The key to success at a site like this is to have a lot of time to explore and to be prepared. I regret that I had not studied any of the books I mention above until AFTER I got home!

--Edited by Vicki Lais

Photos by Larry Hensley

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trackways

August 19, 2000 - The BPS Track Meet

May 28, 2000 - Pennsylvanian Fossils, Walker Co, AL

March 19, 2000 - Pennsylvanian Fossils, Walker Co, AL

January 23, 2000 - Pennsylvanian Fossils, Walker Co, AL

November 20, 1999 - Bibb Co, AL

Photos by Larry Hensley

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