00870cam a22002411 4500 gs 06001021 DLC 20260227111304.0 770117s1892 dcua f000 0 eng c gs 06001021 (OCoLC)2683129 U.S. Geol. survey. Lib. WKenU DLC premarc QE656 .W2 Walcott, Charles D. (Charles Doolittle), 1850-1927. The North American continent during Cambrian time / by Charles D. Walcott. Washington, Gov't. print. off., 1892. 523-568 p. pl. XLII-XLV (incl. double maps) diagrs. 31 cm. Cover title. Extract from the 12th annual report of the director of the U.S. Geological survey, 1890-91, pt. I. Geology, Stratigraphic Cambrian. Geology North America. 24497 24497