﻿Geology and Natural History. 321 



teropods, of which 66 are new : Cephalopods and Brachiopods are 

 relatively poor in species. 



New York Devonian Geology. — H. S. Williams, of Cornell, 

 presented a revision of the Cayuga Lake (N. Y.) Section of 

 Devonian, and reached the conclusion that the Hamilton fauna 

 was not interrupted by the limestones associated with the Coral- 

 line beds, and that the Moscow shales also include only a modi- 

 fied stage of the Hamilton fauna, but that the true Tully lime- 

 stone, whenever it is distinct, interrupts the Hamilton fauna, and 

 is associated locally at least with the overlying deposits called 

 Genesee, with which it should be connected more intimately than 

 with the Hamilton below. 



A second paper by the same author, based on his paleonto- 

 logical studies, and illustrated especially by species of Stropho- 

 menidae, described the initiation of genera and species in the geo- 

 logical series. Wide variation was found to be developed soon 

 after the first appearance, and species in later horizons did not 

 seem to accumulate additional variation, but rather to persist in 

 forms previously defined : a genus thus appears plastic at first, 

 and fixed afterward. 



Mr. Walcott mentioned that the trilobites present similar char- 

 acteristics in their first appearance and later continuation. 



Connecticut Valley Triassic. — A process of mechanical defor- 

 mation for the Connecticut valley Triassic formation was sug- 

 gested by W. M. Davis, of Harvard, and illustrated by a working 

 model. [The paper will appear in the following number of this 

 volume.] Its essential suggestion was that the faulted mono- 

 clinal structure now possessed by the surface covering of Trias- 

 sic strata was due to their accommodating themselves to the 

 deformation of the floor of tilted schists and gneisses on which 

 they rest. Professor Newberry thought the suggestion would aid 

 the solution of the old Triassic problem, but doubted the occur- 

 rence of the reversed faults that it involved; and Professor 

 Emerson believed that it might find support in the attitude of 

 the Triassic beds in Massachusetts, although they presented more 

 irregularity than those of Connecticut. 



Nebraska Geology. — Professor L. E. Hicks reported upon 

 several lines of work that are occupying him in Nebraska. A 

 geological map of the eastern part of the State was first presented 

 in order to give proper relation to the later papers. A series of 

 beds conformably overlying the coal measures, and unconforma- 

 bly covered by members of the Cretaceous formation, was called 

 Permian provisionally, and fossils collected from it by Mr. W. C. 

 Knight were exhibited, among which there were several new 

 types and but few forms known from the coal measures. Profes- 

 sor Newberry questioned the propriety of calling these beds Per- 

 mian ; he knew of no American equivalent of true European Per- 

 mian, as determined by fossils. Mr. Walcott, on the other hand, 

 had regarded certain beds in Arizona as good representatives of 

 the formation in question. Mr. Davis asked whether the speakers 



