Index fossils of North America ... Based on the complete revision and reillustration of Grabau and Shimer's "North American index fossils". [With illustrations.]
Shimer, Hervey Woodburn,1872-1965.
Shrock, Robert R.(Robert Rakes),1904-1993.
New York & London,
[1944]
Joint authors: Hervey Woodburn Shimer and Robert Rakes Shrock.