In response to  Jaggers post, here is a sample of some of the fossils i have collected here in North Texas. I'm amazed at how east they they are to find.

(from top to bottom left to right) The first image is a bunch of ammonite fragments I collected in Denton Texas. I found all these on the same day along with the 2nd image, those are a bunch of sea urchins and clams I found in the same area.

The first on the bottom right are an assortment of ammonites urchins and snails. Some of those fossils are as big as my fist. The middle bottom is another box-o-fossils. The last image bottom left contains one of my best finds. There is a large ammonite that I found next to a holiday Inn in an empty lot (along with a bunch of huge urchins) I also found those ammonites in the first bottom picture there too. Basically In 2 locations I found most of these fossils. The best part was they were just laying on the ground waiting to be found. If you haven't gone fossil hunting in Texas you should try it some time. Its fun and easy.