I also try to take photos and global position information for the more recent localities. I hope to acquire a digital camera in the future to photograph the exposures more carefully. I have a few areas where I have tried to concentrate my collecting efforts. The easiest fossils to collect are those whose shells are made up of calcite. Many shells are made up of the more fragile aragonite.
Calcite tends to remain long after all of the aragonite has dissolved away.
The oysters and scallops tend to fall into this category. Of the remaining species, I hope to add two to my collection in the next few years. The remaining species are so rare that only a few specimens have been found worldwide. The second area of interest are oysters of the genus Pycnodonte . The oldest cretaceous pycnodonte are quite small and nondescript.