brachiopod

On Saturday, March 2, 2019, numerous BPS members and guests traveled through the pouring rain to a fairly close limestone quarry to look for fossils.  The rain stopped by the time we reached the rendezvous location but the temperature began to rapidly drop.  That did not deter any of the fossil enthusiasts nor did it deter our hosts, thankfully!

After a brief lecture in safety and collection from the quarry host, we headed out.  The way to the collection site was slick and muddy but no one got stuck.  We parked in the mud, gathered our tools and headed to the spoil piles to find fossils.  And, as usual, we were not disappointed.  This site has plentiful Mississippian fossils – crinoids, blastoids, bryozoans, brachiopods, and horn corals.  Not so plentiful but also present were several genera of shark teeth.  We all had our strategies planned for finding the elusive shark teeth; some even proved successful.  The quarry chaperones again found nice two Petalodus teeth and maybe more than one BPS member found shark teeth also.  And, as an addendum to last year’s trip report, the large, museum-quality slab was collected and moved to the educational building for sharing – well done!!

At about 2:00, we called a halt to the collecting in order to give the indulgent quarry chaperones the rest of their Saturday.  A handful of collectors reconvened at the nearby (still colorful) Mexican restaurant for refueling and good conversation before the trip home.  This site is so very fun and lucrative for collecting.  I know I’ll look forward to the next visit!

In spite of the freezing cold weather and strong wind, a good group showed up to hunt fossils in an old quarry area, with lots of chert rubble containing mostly brachiopods and crinoids.  Sam found a large, quite rare, crinoid head at the site.

BPS members headed to St. Clair County this month to search for Devonian fossils.  With the past week having numerous days below freezing, we were hoping the predicted 48 degrees would be bearable.  It actually turned out to be a very pleasant sunny day.  After a too-long hiatus from fossil trips, we had members showing up from Huntsville, Birmingham, Mobile, Anniston, Montgomery, and Georgia to spend the day outside digging in the dirt.  Quite literally!   We had been asked to collect soil samples for Jun Ebersole so the first order of business was to collect baggies of dirt. Each person had a card with a number and their name on it and positioned themselves from top to bottom on the hillside.  Their chosen spot was where they collected their soil sample.

After the soil samples were collected and stored away safely, we started searching for fossils.  Though we haven't been to this site in several years, it was not weathered as much as we'd like.  In fact, it's getting grown over, and eventually will be "reclaimed" by mother nature.  Weathering out of the red dirt were numerous bits of corals and sponges, with only a few whole specimens.  Fossils were much more difficult to find on this trip, and most of what we found on the surface were worn and broken.  In one area, a few impressions of archimedes and crinoids in Ft. Payne chert were found. Some of rocks in the area are light yellow sandstone or siltstone, and split rather easily.  Inside are mostly brachiopods and trilobites.  Normally we find only the trilobite cephalon (head) at this location, but this time we also found several pygidiums (tail). On a large limestone boulder high on the mountain, and very difficult to reach, is the impression of a gastropod and "something else".

On 11 April, BPS visited a quarry in Morgan county.  After signing in and filling out all the release forms we were escorted to the dig site.  The quarry contains limestone, and the fossils found were primarily from the Mississippian Period of the Paleozoic Era. 

The Mississipian Period is known as the "Age of Crinoids". This period spanned approximately 360-320 million years.  It was named for the exposed rocks in the Mississippian River valley near St. Louis by geologist Alexander Winchell in 1870.  The quarry visited was mining limestone.  Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3).  Shells and other marine byproducts settle on the ocean floor and are compressed for millions of years as layer by layer of the calcite are depostited.   Limestone also contains variable amounts of silica, chert, sand, silt and other impurities.  It can be crystalline, clastic (composed of fragments of other rocks), granular or massive  depending on the method of formation.  

We had an excellent turn out.   It turned a bit cold, but that didn’t dampen the spirits of the members.

                              
After being briefed by the quarry escorts, who remained with us, we began to spread out and search for treasures.  Most of the material found was in limestone rock, and some was very difficult to extract without heavy chisels and hammers.   

Several Blastoids (Pentremites pyriformise and Pentremites godoni) were found by most on top of the ground in small washes.  Blastoids originated in the Ordovician period and reached their greatest diversity in the Mississippian period.  The picture below shows the main body or theca of the blastoids.  It was protected by a series of interlocking plates made from calcium carbonate.  This was attached to a stalk, which in turn was anchored to the sea floor by a holdfast.  Similar to the Crinoid.  

Most of the blastoids were found on the surface in small washes.  Here Ron is praying to the fossil gods to show him a blastoid as everyone else had found them and he had not.

There were many occurrences of Bryozoans at the site. Several nice finds were made.  Below is a picture of an Archimedes, and Fenestella Bryozoan.  Fenestella bryozoa colonies, are lace-like in construction, and the individual bryozoan animals lived in microscopic tubes or pores on the lace branches.  The fenestrate bryozoan colony called Archimedes lived attached to a screw-shaped support structure.  Most often only the support structure is found.  Bryozoans have existed for hundreds of millions of years (since the early Ordovician) and are common fossils in marine deposits.   Thousands of Byrozoans species exist today all over the world.   
                             
                               

Becky found an unusual item.  James Lamb ( Paleontologist at McWane Science Center in Birmingham, Alabama) was called over to help identify it.  The find turned out to be a nice Petalodus (Petalodontidae (Petalodontiformes) sharks tooth.   It took over an hour and a half to extract it from the limestone it was embedded in.   Becky donated the specimen to the McWane Center museum.  

Here's a closer look at the Petalodus tooth. Petalodus sharks were estimated to reach a length of about 2 meters.  Their basic diet consisted of sponges and other invertebrates. 

A few Brachiopods were also found.   Brachiopods are two valved animals, similar to the bivalves today. 

Most Brachiopods were attached to the bottom by means of a fleshy stalk and were not free swimming like many of the bivalves today.  The Brachiopod in this picture (spiriferina transversa) was 4 cm across.

Not just fossils were found.  Here's one of many calcite crystal clusters that were also found.  Incidently these crystals are simply the crystalline form of limestone (CaCo3).

Many Crinoid and Blastoid stem parts were found on the surface of the collecting area.  

Several specimens of horn coral were also found.  Horn corals are from the extinct order of corals called Rugosa.  Rugosa means wrinkled.  The outside of these corals have a wrinkled appearance.  Horn Coral grows in a long cone shape like a bull’s horn.  The fossil is the skeleton of the coral animal or polyp.  The animal lived at the top of the cone.  They had many tentacles sticking out to gather food.  The tentacles gave the horn coral a flower like appearance.

Several outcroppings of other coral were also found.  The species of coral has not yet been identified.

Leisa found a small trilobite.  The species is not known at this time.   Tiribites are found in many other counties in Alabama.  In the geologic time scale, they came to dominate the seas around 540 million years ago and became extinct around 245 million years ago. 

Here Martha shows her prize of a limestone slab containing numerous fossils.

Here's a closeup of the  limestone slab containing a collection of many different fossils including crinoiod, blastoid, stem parts, archimedes and various other bryozoans. 

Don and Jamie discuss their finds near where many blastoids had been picked up.

Pictures courtesy Vicki Lais and Ron Beerman

Part 2 - More Trip Photos