26o GEORGE M. DAWSON 



Canadian Northwest, collected by Mr. J. B. Tyrrell, were sent to 

 Mr. Wright, and allusion was also made to the report by Messrs. 

 A. Woodward and B. W. Thomas on the "Microscopic Fauna of 

 the Cretaceous in Minnesota, Nebraska and Illinois." ' In this 

 report, all the foraminifera found in bowlder clays, as well as 

 those actually obtained from Cretaceous rocks, are classed 

 together as Cretaceous. 



After carefully examining the Cretaceous material sent, and 

 preparing lists of the forms represented, Mr. Wright notes the 

 occurrence in it of a great preponderance of the two species 

 already mentioned by him as likely to be characteristic. He 

 further points out that these Cretaceous foraminifera are filled 

 with calcite, differing in that respect from most of those of the 

 same age in Great Britain, but none the less stony and unlikely 

 to float during the treatment of the clays. In Yorkshire he 

 has met with clays containing about equal proportions of Creta- 

 ceous (derived) and Pleistocene (contemporaneous) foraminif- 

 era, but found no great difficulty in separating the two lots by 

 the criteria already alluded to. Referring to Messrs. Woodward 

 and Thomas' report, he expresses the belief that it really com- 

 prises a mixed fauna of the same kind, stating that of twenty- 

 nine species recognized by these gentlemen, ten had not before 

 been recorded from rocks of Cretaceous Age, according to Brady's 

 monograph in the Challenger report. 



One of the localities mentioned by Messrs. Woodward and 

 Thomas for foraminiferal bowlder clay, that of South Chicago, 

 lies so far from known Cretaceous outcrops and away from the 

 line of any recognized drift from such outcrops, that I ventured 

 to address a question on the subject of the probable origin of 

 the microzoa to Professor T. C. Chamberlin. The foraminifera 

 found in this bowlder clay, appear to be in part, at least, undoubt- 

 edly Cretaceous in age. In reply. Professor Chamberlin quotes 

 observations made in northern Wisconsin which tend to show the 

 existence of Cretaceous outliers there, as well as perhaps beneath 

 the northern part of Lake Michigan, or even further east. He 



' Geology of Minnesota, Vol. Ill, Part I (1895). 



