Geologic Formation Maps tell us not only the geology of an area but they may also tell us whether that area is fossiliforous or not, and what geologic period it is in. But accessing that information, and the information itself, is far from standardized.
We all travel to some degree, whether from state to state, around a continent, or around the world. This is an international forum.
Wouldn't it be wonderful to access geologic maps from various states, provinces, countries, etc.? If you agree, please post your links to geologic formation maps on this thread, that we may all benefit and perhaps find a common way to access this information worldwide.
I will start. In Minnesota we have the "Minnesota Geologic Survey" through the University of Minnesota. This is a link to a county by county geologic survey for Minnesota. Just click on the county and, technically, you should get the formation maps which will tell you the time periods and whether or not the formation is fossiliferous and maybe even what fossils can be found there - it varies.
Note: They appear to be updating the information and attempting to standardize it, so not all counties are available. And I have found the site to be "stubborn" at times. But keep playing and you will get what you need.
http://www.mngs.umn.edu/county_atlas/countyatlas.htm
Bev :-D