Yоu hаve been prоvided а mаp geоlogists use. Zoom in as far as you need to read and extract information from the map. Tip: if you right-click the map and select "open in a new tab" the map will download to your computer and the clarity of the map will improve when you zoom in. Upon evaluation, you find the symbol representing something called the Monterey Shale. (*this answer is case-sensitive) You determine this is from the period because the first letter of the geologic symbol implies the geologic period of rock formation. The oldest information on the map is from the period. You find this interesting because between these time periods there .