Walcott, Charles D.  1850-1927. <br/><br/>
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. 
<br/><br/> Cover title.  Extract from the 12th annual report of the director of the U.S. Geological survey, 1890-91, pt. I. 
<br/><br/><label>LCCN: </label>gs 06001021  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology, Stratigraphic--Cambrian.<br/>Geology--North America.
<br/><br/><label>LC Class. No.: </label>QE656  / .W2