MUSEUM OF COMPARATIVE ZOOLOGY. 29* 



REPORT ON THE GEOLOGICAL COLLECTIONS. 



By R. W. Sayles. 



For the greater part of the past year the Curator has been 

 absent from the Museum. A large number of labels have been 

 renewed but few acquisitions made. 



An examination was made of 79 microscopic slides of banded 

 slates in the investigation of seasonal deposition. The slate 

 specimens were collected last year by Mr. A. C. Swinnerton under 

 the direction of the Curator, in northern Georgia, southeastern 

 Tennessee, eastern New York, western Vermont, and Cobalt, 

 Ontario. The Late Proterozoic or Lower Cambrian specimens 

 collected from the Hiwassee slate in southeastern Tennessee show 

 distinct seasonal characters, which resemble the characters of the 

 seasonal layers of the Pleistocene and Permian glacial sediments. 

 The banded slates of Lower Ordovician age in northern Georgia 

 likewise show strong seasonal characters. Specimens of shale of 

 the same age from Tennessee taken at Johnson City show the 

 same characters. Specimens of presumably Lower Ordovician age 

 collected at Melrose, N. Y. also show seasonal characters. The 

 specimens of slate taken at Cobalt near the Huronian tillite show, 

 as was expected, good seasonal characters. 



During the coming year it is the purpose of the Curator to make 

 a special collection of sediments to illustrate the different processes 

 in the origin of the conglomerates, sandstones, and slates and 

 shales. 



