Wm. F. Prouty— Meso-Silurian Deposits of Maryland. 563 



Art. LIII. — The Meso-Silurian Deposits of Maryland; 

 by Wm. F. Prouty.* 



The present article discusses briefly the lithological and 

 faunal characteristics of the deposits in the state of Maryland 

 lying between the massive Tuscarora (White Medina) sand- 

 stone below and the Sali.na formation above. These deposits 

 are approximately eight hundred feet in thickness and repre- 

 sent the lower and middle portion of the Meso-Silurian series 

 as shown in western New York. The lower portion corre- 

 sponds to the pre-Rochester Silurian, the Clinton of common 

 usage, while the upper portion is the approximate equivalent 

 of the Rochester, or the lower division of the Niagara group 

 of common usage. 



It is moreover probable that these deposits are equivalent 

 to the typical Clinton of Hall exposed at Clinton, Oneida 

 County, N. Y. The latter, according to both E. O. Ulrichf 

 of 4he IT. S. Geological Survey and to C. A. Hartnagelf of the 

 New York Survey, contains in its upper portion a fauna equiv- 

 alent to the Rochester or Lower Niagara fauna of western 

 New York. It is very unfortunate that the fauna of the typ- 

 ical Clinton should have gone so long unstudied, thus allowing 

 at the present a double meaning of the term Clinton, as seen 

 below. 



The Meso-Silurian deposits of western New York and the 

 interior may be subdivided as follows : 



(3. Guelph 

 [ B. Niagara <( 2. Lockport 

 | ' I *• Rochester 



Meso-Silurian \ 



I 



[ A. Clinton 



while the Meso-Silurian deposits of eastern New York, Penn- 

 sylvania, Maryland, etc., may be subdivided as follows : 



' 2. Rochester of com- 



Meso-Silurian ■! A. Typical Clinton { _ ni . , p 



I * 71 ' 1. U font on oi common 



usage 

 I shall not enter into a discussion of the nomenclature, but 



shall use the term Clinton in the restricted sense to include 



only the portion below the Rochester. 



In the study of the Maryland Meso-Silurian deposits all the 



important exposures in the state have been visited and at each 



* Published by permission of the Director of the Maryland Geological 

 Survey. 



f From letters of recent date. 



