Wilmarth, M. Grace  1866-1949, <br/><br/>
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 .
<br/><br/>Bibliographical references. 
<br/><br/><label>LCCN: </label>gs 25000068  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology, Stratigraphic.<br/>Geological time.
<br/><br/><label>LC Class. No.: </label>QE75  / .B9 no. 769