All the small fossils were found walking creeks in around the Waco to Whitney area, the big ones (nautilus shells,I think)were found back in the 80's when I worked the oilfields near Big Lake. When roads were being built cliche pits were dug for road base material. Road graders would just push these to the side, all I had to do was drive slow and just pick 'em up. Some would be embedded in the road, so I would have to use my shovel to get them out..made work fun!!!!!!I've got 16 big ones and several smaller, the small ones have the best detail...happy hunting!
The term Nautilus would be the Genus of the species. These are of the species ammonite. I have found specimens of ammonite up to 6 feet in diameter in cretaceous age limestone outcrops in Crane and Pecos Counties, Tx. The fish encasements are quite nice.