00900cam a22002291 4500 gs 25000068 DLC 20260227111329.0 830606s1925 dcua b f000 0 eng gs 25000068 (OCoLC)9580315 DLC MWalB OrPS DLC QE75 .B9 no. 769 Wilmarth, M. Grace (Mary Grace), 1866-1949, comp. The geologic time classification of the United States Geological survey compared with other classifications, accompanied by the original definitions of era, period and epoch terms. A compilation by M. Grace Wimarth. Washington, Govt. print. off., 1925. vi, 138 p. pl. (fold. tab.) tables. 23 cm. U. S. Geological survey. Bulletin 769 Bibliographical references. Geology, Stratigraphic. Geological time. 26364 26364