Where’d You Dig Up That Old Fossil?!?

It’s the beginning of Earth Science Week!  Hooray!  What is Earth Science Week you ask?  It was started in 1998 by an organization called the American Geosciences Institute with the following objectives (from the AGI website):

“To engage students in discovering the Earth sciences.

To remind people that Earth science is all around us.

To encourage Earth stewardship through understanding.

To motivate geoscientists to share their knowledge and enthusiasm about the Earth.”

Pretty good objectives that can be related to our TMN mission statement, I think.  Educating the public and promoting good stewardship of the land.  This year Earth Science Week runs from October 12th to 18th.  So in light of Earth Science Week I present, the Stone City Fossil outcrop!

Railroad Bridge over the Brazos River at the Stone City Fossil Site

Stone City Fossils

It’s been called one of the most fossiliferous locations in Texas. The fossils here were deposited about 35 million years ago during the Eocene Epoch of geologic time. The rock type is a sedimentary rock meaning the rock is composed of sediment that has been compressed over time. However, because the rock here isn’t that old (in geologic terms!) it’s actually soft enough to dig into and that makes it perfect for locating fossils.

Loose fossils weathered out from the rock.  Pictured are gastropods (3 in the center), an oyster fragment (large piece to the left) and a pelecypod (to left).

The location is also called the Whiskey Bridge Fossil Site because legend has it that back in the old days Aggies desperate for a drink would cross the bridge over the Brazos River to get into Burleson County.  I prefer the Stone City name since it refers to formation name (where ‘formation’ is just another word geologists use to say ‘rock layer’).  The rock layer was named for the little town that used to exist here.

Fossils are the remains of organisms that lived in the geologic past and finding them in rocks can give you a great clue about Earth’s past environments. Today, certain animals and plants are only found in specific areas so, for example, whales are in the marine environments and bears are terrestrial. That’s exactly how it was in the geologic past. Each organism lived in a specific geological environment. Therefore, geologists can use fossils to interpret whether a location was on land or under the ocean and can get water depth, water temperature, salinity, and more.

Fossils in place in rock.  Large gastropod on the right called Conus.

More fossils in place.  Large pelecypod in center.

The Stone City fossils tell geologists that during the Eocene, 35 million years ago, the Bryan/College Station area was under about 100-200 feet of ocean water…. much different than today! Common fossils include gastropods (snails), pelecypods (clams), corals, ootoliths (fish ear bones), bryozoan, and you can sometimes find sharks teeth and squid beaks. Overall there are about 50 different types of fossils that can easily be found here. This is a great location for kids when the water is low so feel free to bring the little ones!

Hand-sample of the rock with gastropod fossils. 

Want to visit the site?

If you are going to visit the site, there are two parking areas here… one to the west side of the bridge on Hwy 21 and one to the east.  Both sides of the river contain fossils so either parking area can be used.  However, if the river is running a little high or it’s rained recently, the eastern bank of the river may be under water. Please stay on the county property near the bridges.

If you don’t want to go on your own… The Houston Gem and Mineral Society will be sponsoring a free field trip to the site on October 19, 2014, from 12-3 pm. Experts will be on hand to share their knowledge and answer any questions you may have.  More information can be found at: https://www.hgs.org/civicrm/event/info?reset=1&id=1492

And this counts as advanced training!

SAFETY NOTES!

1) There is POISON IVY here so beware!

2) Do not visit this cache when the river is high! The fossil site will be underwater and dangerous to approach. Also, right after the rain the location will be very muddy and possibly challenging. Use common sense and visit this site when the river is low.

References:

Earth Science Week: http://www.earthsciweek.org/about-esw

Stone City:  http://www.tshaonline.org/handbook/online/articles/hrs68

Fossil Info from the Houston Gem and Mineral Society: https://www.hgs.org/civicrm/event/info?reset=1&id=1492