I purchased a lot of specimens from a member of the Fossil Forum recently that were from the Cretaceous and upper Carboniferous (Pennsylvanian) of Texas. All the fossils had been personally collected by Dan Woehr and you can read about his trips at his "Meanderings of a Texas Fossil Hunter" website. You've seen some of the Brachiopod specimens from the Finis Shale that I have acquired from Estate sales but today I wanted to illustrate some of the common Gastropods that Dan sent me.
Straparollus sp. Note that one side of the shell is flat while the other is raised. This indicates to me that the snail dragged the shell across the bottom rather than having it hoisted above it's body as most snails do.
There are those who say that you should never buy a fossil that you could collect yourself. While this has some merit, my prime motivation for purchasing these fossils from Dan is two fold. First, these make good study fossils for me to compare to those I might find in other areas (including here in Pennsylvania). Second, who knows when I will be able to get down to Texas to do my own collecting and if I would have the opportunity to collect all of the above species during a trip. If I purchase fossils I like to do so from the same people who found and collected the specimens. This way I have a knowledgeable local person whom I can ask questions about the fossils and I know they are taking the time and effort to make sure the specimens are correctly labeled and carefully packed. Support your local fossil collectors!