Trans. N. V. Ac. Set. 20 Nov. 12, 



Prof. J. S. Newberry read a paper on 



THE RELATIONS OF DINICHTHYS, AS SHOWN BY COMPLETE CRANIA 

 RECENTLY DISCOVERED BY MR. JAY TERRELL, IN THE HURON 

 SHALE OF OHIO. 



Drawings of these crania were exhibited. They showed that the head 

 was shorter and broader than was formerly supposed, and confirmed 

 the views expressed in the Report of the Geology of Ohio, that 

 Dinicht/tys was closely allied to Coccosteus, but was a hundred times 

 larger. The cranium of Dinichthys was strongly arched in life, but 

 is flattened by compression in the fossil state. It is then triangular in 

 outline, nearly three feet broad behind, and two feet long. The brain 

 box was partly cartilaginous, but was enclosed in strong, continuous 

 plates of bone. The fin rays and some of the vertebrse were ossified. 

 The head was articulated with the body by the strongest, most com- 

 plex and complete osseous joint yet found in nature. 



November 12, 1883. 

 Lecture Evening. 



The President, Dr. J. S. Newberry, in the Chair. 



Fifty-eight persons present. 



The President stated that the crystals of a mineral from 

 Laramie City, presented at the last meeting by Mrs, Weld, 

 had been examined by Prof. Brush, of New Haven, who re- 

 ported that they appeared to consist of aragonite, although 

 enclosing some minute rhombohedral crystals, apparently of calc- 

 spar; but that he had never seen aragonite crystals possessing 

 the same bevelled edges. The variety was entirely new. 



Dr. Hubbard W. Mitchell then delivered a lecture, illus- 

 trated with diagrams and stereopticon, upon 



THE SUCCESSION OF ANIMAL LIFE ON THE GLOBE. 



November 19, 1883. 

 Section of Geology. 



The President, Dr. J. S. Newberry, in the Chair. 



Forty persons present. 



A Communication was received from Dr. H. Carrington Bol- 

 ton, of Hartford, Conn., presenting two specimens of a minute 

 gasteropod, which had been recently found in great numbers upon 



