Collier, A J. <br/><br/>
United States Geological Survey Bulletin ;   no.736-F 

 - Washington-US :   United States Geological Survey Bulletin,   1922. 
 - páginas 171-178 :   IIustraciones blanco y negro 
 - No. 736-F (1922) 
 - United States Geological Survey Bulletin ;   no.736-F .
 - United States Geological Survey. .