Waco Lake Research Pit

September 22, 2013

I have planned a Paleo field trip to the Waco Lake Research Pit on Sunday,
September 22, 2013. We will talk about it briefly at our September 17 Paleo meeting.

If you plan to go, I will need an e-mail response as soon as possible with the following information. I must inform the US Army Corps of Engineers on the number of people going in–this must be put on the permit.

Name or names (if you have riders)
Type of vehicle
Color of Vehicle
Vehicle license number

We will meet at the Research Pit parking lot between 8:00 and 8:20 a.m. It takes about 3 hours to get there from Southwest Houston.

We will head into the pit by or before 8:30 a.m. Children are allowed in the pit, but you cannot leave them there.

Where to go? The address of the COE office in your GPS will get you there. 3801 Zoo Park Dr., Waco, TX. You will get to the Pit parking area first (which will be on your left), so do not go all the way to the COE office..

This Google map link will show you where to park and the location of the COE office. Turn on the satellite view to see the parking area by the pushpin. You can see the map if you copy and past this into any browser, or highlight it, click right, and then click on “open link in new window” and then print the map.

What will you find there?

The Waco Pit was excavated to provide material for the Waco Lake dam. The pit cuts into what most Texans call the “Del Rio Clay” (approximately 95-ish million years old), exposing a number of great fossils. Also known as the Grayson Formation, Grayson Marl, Del Rio Shale, etc., depending on what source you consult. In any case, it is Cretaceous, Cenomanian Stage, and is in the middle of the Washita Group sandwiched in between the underlying Georgetown Formation and the overlying Buda Limestone on the Texas geological map.

A person can observe pyritized fossils of ammonites of various types, gastropods, bivalves, and a few other things that occasionally get pyritized. Most of the fossils you will see are small.

Also found are other fossils (this list borrowed from Lance Hall), such as

Ammonites: Adkinsia, Engonoceras, Mantelliceras, Scaphites (loose coiled); Heteromorph ammonites: Plesioturrilities, Mariella; Baculites: (straight shelled ammonite); Nautiloids: Cymatoceras, rhyncholites (beaks); Echinoids: Coenholectypus, Goniophorus, Salenia, Cidaris? (spines, plates); Asteroids: starfish, brittle stars; Gastropods: Turritella; Shark teeth: Cretalamna, Leptostyrax, Ptychodus, others; Fish: Pycnodont teeth, loose vertebrae; Oysters: Gryphea, Ilymatogyra, Plicatula; Scallops: Neithea (Pecten); Brachiopods: Waconella (Kingena); Coral: solitary corals

I would suggest clothing that is weather-appropriate and poison ivy protective. Bring something to eat, and lots of water to drink. Don’t forget sun protection. Ziploc bag or small container for your fossils. A backpack or some other bag should be enough to carry all of your stuff. I also like knee pads when I collect.

The pit is a lot bigger than it looks, and it takes quite a while to maneuver around should you decide to try to explore the whole thing. You probably cannot circumnavigate the pond completely without getting wet or getting into a lot of thick vegetation. There is a monster that lives in the pond, so look out! I’ve seen a duck vanish from the surface.

Do not bring a big shovel or rock pick-the COE frowns on that. A screwdriver or small implement is all you will need anyway.