Cambrian and Ordovician / Maryland Geological Survey.
Maryland Geological Survey.
Bassler, Ray S. (Ray Smith), 1878-
Baltimore :The Johns Hopkins press,1919.
At head of title: Maryland geological survey.
"The seventh of a series of reports dealing with the systematic geology and paleontology of Maryland."
Versos of some of the plates on which explanations are given are numbered as pages.
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