206 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



not to have been considered. The interpretation of the graptolite beds as delta 

 deposits formed near the mouths of kirge rivers and repeatedly flooded by the 

 sea, resulting in the stranding on the mud-flats of the planktonic or epi-plank- 

 tonic graptolites, will be discussed in the light afforded by such sections as 

 those of the Moffat district of Scotland, the Scandinavian region, Bohemia, 

 Wales, and North England, and the Hudson River region of North America. 



A second paper on the subject of graptolites completed the program 

 for the day. Discussed by Messrs. Grabau, Schuchert, and Chadwick. 



GRAPTOLITE ZONES OF THE UTICA SHALE 

 BY RUDOLF RUEDEMANN 



{Abstract) 



Four zones have been distinguished in the Utica shale of the Upper Mohawk 

 Valley and Black River Valley. The type section in the city of Utica is within 

 the third zone ; the fourth zone is found in the Black River Valley. 



After deciding to attend the Symposium on Sedimentary Eocks, on the 

 program of the Geological Society of America at 10 o'clock the following 

 morning, the Society adjourned at 5.30 p. m. 



At 8.15 o'clock thq members convened in Chancellor's Hall of the 

 Education Building and listened to the address of Dr. John M. Clarke, 

 retiring President of the G-eological Society of America. 



At 9.15 the members joined the Fellows of the Geological Society of 

 America at the smoker given at the University Club. 



Session of Friday, December 30 



The Society did not meet until 11.30 a. m. to continue the regular 

 program on account of attendance at the Symposium on SedinT^utary 

 Eocks, under the auspices of the Geological Society of America. The 

 subjects and speakers of this symposium -were as follows: 



SYMPOSIUM ON THE INTERPRETATION OF SKDI3IEXTARY ROCKS 



THE PROBLEMS STATED 

 BY A. Vf. GRABAU 



SiaNIFICANCE OF SEDIMENTARY RHYTHM 

 BY jose;ph BARRELL 



