rugosa coral

March 29, 2003 - Morgan and Lawrence Co, AL

This month, BPS visited the "education center" of a local Jefferson County quarry, where school children are taught about quarry operations in a nice building with a great view of the quarry, and a small working model of the conveyor activity. Inside, there were numerous fossil displays exhibiting fossils from many of their quarry locations around the south. Upon seeing several whole crinoids on display, we were practically drooling to get going on the collecting trip. The group then drove to a quarry in Morgan County, Alabama. This was a site where no one had collected before, other than quarry personnel, and what a fine group of specimens were found! Large blastoids, crinoids, horned coral, and archimedes were our primary finds. At least 6 whole crinoids were found, and the excitement of the members upon finding yet another of these wonderful specimens was very exciting! Due to the unusually chilly, overcast weather as compared to the prior few weeks, no rattlesnakes were spotted, though our leader said he had encountered 4 of them last summer.

(Photos courtesy Ron Beerman, Bill Cunningham, Greg Mestler & Vicki Lais.)

Several whole crinoids were found on the trip; this one by Vicki.

Several BPS members diligently searching the spoil piles.

Greg dissolved a slab of limestone he took home and found these crinoids inside.

Numerous blastoids, crinoid parts, and horned coral were found.

Crinoids found by Jan and Claire.

Found by Ron.

Found by Bill.

The view from the collecting site.

Outcrop of rugosa coral.

Found by Ron.

Bill and Adele in foreground, Leisa in background.

Looking in all the cracks and crevices.

More of Ron's finds.

Our third stop of the day was at a roadcut in Lawrence County, Alabama, where numerous specimens of rugosa coral, including whole coral heads the size of boulders, were found. There was even a small cave-like cavity in the ground that had been uncovered, where one could peer in and see a small, undisturbed area of coral in place. Both collecting sites were in the Bangor Limestone.

More rugosa coral, from the second site of the day.

February 26, 2000 - Mississippian Fossils, Franklin Co, AL

Every year, the BPS visits a lake in Franklin County, Alabama when the lake level is down from normal, exposing rocks from the Bangor Limestone dating back to the late Mississipian Period of geological history (about 320 million years). About 25 BPS members and guests attended the field trip, which took place on a beautiful, sunny, and pleasantly warm day.

According to Jim Lacefield, the Bangor Limestone formation is "fossiliferous from top to bottom, and collecting sites in it in both Colbert and Franklin Counties are world famous for echinoderms - particularly for crinoids and blastoids - and bryozoans such as Archimedes." Indeed, there are numerous sites in Alabama connected with this formation, and Jim says it is the best rock unit in Alabama for Mississippian fossils, and that few other units are better anywhere for the time frame in question.

We all parked our vehicles along an access road by the lake, and then walked out along the rocky, sandy shoreline. It was in these areas where we found a variety of interesting fossils: blastoids, crinoid stems and loose stem plates, Archimedes spirals, brachiopods, and horn corals. Unfortunately, my camera malfunctioned while I was at the site, so I have no pictures of the lake itself or the sandy shores.

--Edited by Vicki Lais

Fig. 1 -
examples of blastoids over a range of sizes.

Fossils were found in two "modes":
loose specimens lying in the
sand, or encased specimens lying in strong limestone matrix. I show
pictures of specimens in both modes here. The first picture shows a
variety of blastoids from the sand, up to a penny in size. These were
quite common and everyone there found at least a few if they got down
on their knees and looked closely at the sand. Much larger blastoids
have been found at this site. I recall two years ago how Ken Hoyle
picked up a giant blastoid 1-2 inches in length. This kind of blastoid
is much rarer than the pieces in the
photograph.

According to the Fossil Handbook by Rich et al. (1996),
blastoids
represent stemmed echinoderms whose top sections resemble petrified
"nuts". The pieces in the picture represent the calyx of the original
animal. Fine details are usually seen in the calyx, such as ridges, a
five-fold symmetry, and small holes around the apex representing mouth
and possibly anus.

The second photograph shows a variety of crinoid columns (or stems), some with unusual side holes that I think represent nodes where possibly small branches emerged. Typically these pieces are less than an inch in length, and some have interesting five-petaled flower or star designs on stem plates (columnals) themselves. Even single stem plates could be found in the sand. The third photograph shows loose "Archimedes" spirals or corkscrews. These represent a type of animal known as a bryozoan, or moss animal. Archimedes spirals are members of a group of bryozoa known as Cryptostomata, that includes the lacey grid-like fossils seen on other larger rocks from the same site. The two features were part of the same animal according to the Fossil Handbook. The authors of the Fossil Handbook state that the combination of a lacey support and a central column in the form of a wide-flanged corkscrew was an efficient feeding arrangement.
	Fig. 2 - examples of short sections of crinoid stalks, some with nodal holes.


	Fig. 3 - examples of Archimedes corkscrew bryozoa.

The fourth photograph shows a variety of small horn corals. According to the Fossil Handbook, these belong to the group Rugosa because their surface is marked by wrinkles. Most of the pieces I found were weathered and in poor condition.
	Fig. 4 - examples of small Rugosan horn corals.

The remaining photographs show a variety of small brachiopods, Archimedes spirals and crinoid stem plates encased in a limestone matrix. The last picture is typical of many Mississipian rocks in northwest Alabama: showing hundreds of loose crinoid stem plates. Although I was able to stay at the site for only an hour and a half, it was still possible to find many interesting specimens. Unfortunately, I missed the highlight of the trip: a visit to the home of Jim and Faye Lacefield in Tuscumbia. It was very kind of Jim and Faye to invite the BPS to their home, and I heard from those who went that it was a very nice experience.
	Fig. 5 - examples of small brachiopods.


	Fig. 6 - rock with two strong Archimedes spirals encased.


	Fig. 7 - piece covered with crinoid stem plates and bryozoa.

The BPS will continue to visit this area, probably
at least once a year. The possibility of finding interesting
Mississippian fossils is always present at this site, and it is a trip
worth looking forward to each year.

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rugosa coral

March 29, 2003 - Morgan and Lawrence Co, AL

February 26, 2000 - Mississippian Fossils, Franklin Co, AL

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