76 IOWA ACADEMY OF SCIENCE 



M. M. Leighton of the Iowa Geological Survey. Their investi- 

 gations have confirmed the contention of Doctor Calvin that 

 in northeastern and north-central Iowa there is an Iowan drift. 

 In September, 1915, after the completion of the field work of 

 Alden and Leighton, a conference was held in the Iowan area, 

 in which conference Dr. W. C. Alden, Mr. Frank Leverett, Dr. 

 R. D. Salisbury, and the writer participated. After a critical 

 study and discussion of the main lines of evidence in the field, 

 agreement was reached by all that there is a post-Kansan drift 

 to which the name "Iow r an" was given by Calvin. 



A report of the investigation of Doctor Alden and Doctor 

 Leighton is now being prepared for publication by the Iowa 

 Geological Survey. 



Much of the evidence in connection with the Iowan is very 

 elusive, and the fact that Doctor Calvin, who was regarded 

 for many years not as a Pleistocene geologist but as a paleontol- 

 ogist, correctly interpreted the evidence indicates his keen pow- 

 ers of observation and his ability to discriminate evidence which 

 one geologist has said "defies the experts." 



Department of Geology, 

 State University. 



