8 proceedings of rochester meeting. 



Session of Tuesday Morning, August 16 



The Society assembled at 10.15 o'clock a m, President Gilbert in the 

 chair. 



The first paper read was — 



PHASES IN THE METAMORPHISM OF THE SCHISTS OF SOUTHERN BERKSHIRE 



BY WILLIAM II. HOBBS 



This paper is published elsewhere in this volume. 



The next paper was then presented by the author, and was illustrated 

 with maps and drawings: 



THE ONEONTA SANDSTONE AND ITS RELATIONS TO THE PORTAGE, CHEMUNG 



AND CATSKILL GROUPS 



BY .1 i.MES HALL 



During a long discussion, Professor H. S. Williams spoke as follows : 



It is difficult to map such formations, the physical conditions of deposition being 

 related to the faunas in a very complicated manner. The physical conditions 

 change the character of the deposits, while the fauna may persist; a series of dis- 

 similar rocks being together one faunal formation. In determining the extent of 

 formations paleontology outranks lithology. 



In reply to a question by Professor J. J. Stevenson, Dr Hall said — 

 The Chemung wedge is lithologically distinct as well as in its fossils. 



Professor Stevenson compared Dr Hall's section of strata with his own 

 New York section and with Professor I. C. White's observations in Penn- 

 sylvania. Professor White stated that a similar formation extends from 

 New York to White Sulphur springs, in Virginia, and even into Ken- 

 tucky. He -would call it all Chemung. Professor E. W. Glaypole spoke 

 in compliment of the paper, which contained observations made before 

 many Fellows of the Society were born. He said that in Ohio shales re- 

 place the sandstones of New York and Pennsylvania. During Devonian 

 time physical conditions greatly changed in a few hundred miles from 

 east to west; in western Pennsylvania changes occurred within an extent 

 of only twenty-five miles. The President spoke of the classification of 

 formations and the principles of nomenclature, and remarked that nature 

 is more transitionary than our nomenclature can adequately present. 



In closing the discussion Dr Hall spoke of the Long persistence of 

 faunas, through important changes of receding and readvancing sea- 



