The Central Texas counties surrounding Limestone County are full of beautiful ancient marine shells replaced by calcite, both massive and crystallized. Luckily for the collectors of minerals and fossils, hundreds of miles of low traffic roads in Central Texas contain a wide variety of ancient sea life replaced by calcium carbonate. They are up on the surface of gravel and dirt roads, as snowy white gravel, stretching down the country lanes.
This area of collecting is centrally located between Interstate 35 and 45. Those highways run through Texas, connecting San Antonio, Austin, Houston and Dallas. In between this area, vast deposits of limestone of a very high quality are found and mined for agricultural and industrial use. It is often found as crushed aggregate used to cover the stone roads of back country Texas. Spiraling out of the central texas area like a web connecting new developments with well maintained farm routes, the white roads of Texas are often found to contain calcite crystals and calcite replaced marine shell fossils. Clams, Brachiopods, Turritella, Ammonites and other interesting shells are found, often with cores and voids filled with crystals of calcite.
Getting to a collecting location is simple! Simply pull up Google Maps and take a look at a satellite view of Central Texas. As you get closer, look out for maintained county roads, which you will see, are bright white. This white color is caused by this limestone gravel. Make a note of these roads to inspect and take a trip to Marlin, Mart, Rosebud, Franklin, Calvert, Madisonville, and Crockett. Since there is ample loose gravel, do not DIG into the road or bother to take tools with you. Loose Gravel. Mostly made up of calcite replaced shells. What an amazing collecting experience. Simply opening your car door will result in you finding a loose fossil. With smartphones, androids and iphones, simply using google maps while navigating will be all you need for a spur of the moment collecting trip. This area is a little over 3 hours from San Antonio, a quick 2 hours from Austin, Houston and Dallas. It is a PERFECT field trip in all weather besides tornadoes and snow!
