44 The Middle Detoxiax Deposits of Maryland 



and has been correlated with that stage by the writer. The Genesee shale 

 was orignally chissed in the Hamilton series but later writers have shown 

 that its fauna is more closely related to that of the Senecan series in 

 which it is now generally placed. It is not clear to the writer from the 

 descriptions of the Eomney formation whether this shale occurs in West 

 Virginia or not but if present it is thought to be included in the Romney 

 formation since it is stated that " The loAver members [of the Jennings 

 formation] are light-colored shales, in which olive-gray and buff tints pre- 

 dominate, with interbedded light-colored sandstones, some of which are 

 moderately thick bedded." ' In Allegany County there is quite a rapid 

 change from the coarser bluish, or olive shales when weathered, of the 

 Hamilton into the fissile black shales of the Genesee. This line is fully 

 as distinct and sliarp as that separating many formations and it has been 

 selected by the writer as the line of division between the Eomney and 

 Jennings formations. This division agrees with the accepted classitica- 

 tion of the Hamilton or Erian series of Xew York and if not strictly 

 in accordance Avith the former limit of the Romney shale it is believed 

 that since a precise line was not indicated for the top of that formation, 

 the change is not great enough to necessitate a new name for it. This 

 change simply tends to fix the upper limit of the formation more precisely 

 than was done in the former descriptions and it is thought that it will 

 introduce no confusion concerning its limits because the Genesee shale 

 had not been identified or mentioned as a part of the formation. 



The evidence given above for correlating the Eomney shales overlying 

 the Onondaga member, wiih the Marcellus and Hamilton stages of New 

 York is considered conclusive, especially when it is taken into considera- 

 tion that other sections in the Middle Devonian rocks of southern Penn- 

 sylvania, Marj'land, and northern West Virginia present a similar array 

 of facts in favor of such correlation. This will be shown in the account 

 of other sections in Allegany and Washington counties as well as in the 

 typical area of the Romney formation near Romney, Hampshire County, 

 West Virginia. In Pennsylvania, Professor Stevenson identified these 



'Ibid. 



