June 1906. Devonian Fossils — Slocom. 261 



only in and below the Encrinal limestone at Eighteen Mile Creek, 

 but at Bethany it occurs both above and below. Stropheodonta 

 detnissa is found throughout the series at Bethany, and also at Thed- 

 ford, but at Eighteen Mile Creek it is reported in the Encrinal bed 

 and below, and at Cayuga Lake only in the Hamilton. Tropidoleptus 

 carinatus is found through the series at both Bethany and Cayuga 

 Lake, but at Eighteen Mile Creek in the Encrinal limestone and be- 

 low, and at Thedford only in the Hamilton. 



It is of interest to note that in the Bethany fauna the range of 

 some species, e. g. Aulopora serpens and Tropidoleptus carinatus 

 corresponds to the Cayuga Lake fauna; that of others, e. g. Stroph- 

 eodonta demissa, corresponds to the Thedford fauna, and Stropheodonta 

 concava and Favosites argus have as great a range at Bethany as at 

 all the other localities combined. Hence it is not safe to determine 

 the position of isolated beds, in regard to the Encrinal limestone, 

 by the composition of the fauna. A similar conclusion was reached 

 by Cleland* in his study of the Hamilton beds at Cayuga Lake. 



The following table represents the amount of material collected 

 by the writer, with the exception of the bryozoans from "B8." Of 

 these a large series, both of species and specimens, was secured, but 

 as they have not yet been identified, they are not included. The 

 figures against each species in the table indicate the number of speci- 

 mens collected by the writer. The letters indicate that the same 

 species have been reported by other authors from Thedford, Eighteen 

 Mile Creek, or Cayuga Lake, and the particular letter indicates the 

 bed in which they were found. Thus M, indicates Moscow shale; 

 E, Encrinal limestone, and H, Hamilton shale. The papers con- 

 sulted for mention of these species are the following: Hamilton 

 Group of Thedford, Ontario, by H. W. Shimer and A. W. Grabau, 

 Bull. Geol. Soc. Am. Vol. 13, p. 149, 1901 ; Geology and Paleontology 

 of Eighteen Mile Creek and the Lake Shore Sections of Erie County, 

 by A. W. Grabau, Bull. Buffalo Soc. Nat. Sci. Vol. VI, 1899; A 

 Study of the Fauna of the Hamilton Formation of the Cayuga 

 Lake Section in Central New York, by H. F. Cleland, Bull. 206, U. S. 

 Geological Survey, 1903. 



* Bull. 206. U. S. G. S., p. 91. 



