16 PROCEEDINGS OP THE INDIANAPOLIS MEETING. , 



into one another. This would also agree with its extremely irregular shape.. Such 

 local subsidences are in harmony with what we know has occurred. If the channel 

 of Mozambique between Africa and Madagascar has sunk 1,000 fathoms since middle 

 Tertiary days, apparently without affecting the adjoining land to any great extent 

 (and many similar cases could be quoted), there is nothing contrary to probability in 

 believing that the same thing has happened elsewhere and repeatedly, or in regard- 

 ing the oceans as the result of many such changes rather than as aboriginal features 

 of the earth's surface. 



Akron, Ohio, August 15, 1890. 



The paper was discussed by C. H. Hitchcock, J. J. Stevenson and E. W. 

 Claypole. 



The next paper was entitled — 



THE CUYAHOGA SHALE AND THE PROBLEM OF THE OHIO WAVERLY. 

 BY C. L. HERRICK. 



The paper was discussed by H. S. Williams, E. W. Claypole, I. C. White, 

 A. S. Tiffany and C. L. Herrick. It is published elsewhere in this volume. 



The next communication was on — 



THE TACONIC ORES OF MINNESOTA AND OF WESTERN NEW ENGLAND. 



BY N. H. WINCHELL AND H. V. WINCHELL. 



The communication was discussed by C. H. Hitchcock and N. H. Win- 

 chell. It is printed in full in the American Geologist, vol. vi, 1890, pp. 

 263-274. 



This paper was followed by — 



WHAT IS THE CARBONIFEROUS SYSTEM ? 



BY H. S. WILLIAMS, 



[Ahsti-act.) 



The confusion which arises from a lack of precise definition as to the constitution 

 and limitation of the Carboniferous system has led to the preparation of this paper. 



The earliest English author who appreciated the importance of grouping certain 

 rock formations with the Coal Measures to form what now is called a system was 

 W. D. Conybeare."^ The German geologist Werner and the school of geologists that 

 followed him called the Coal Measures the " Independent Coal formation " or " Stein- 

 kohlengebirge." Conybeare subdivided the " Transition and Secondary formations" 



* Conybeare and Phillips, Outlines of the Geology of England and Wales. London, 1822. 



