A r . H. Darton — Upper Silurian rocks. 209 



This, I believe, is the first Verticordia described from the 

 Eocene, there having been only three species known among 

 living and fossil shells, two of these being Miocene. Differs 

 from V. Emmonsii Con., in being rotund and having more ribs, 

 and from V. cardiiformis Wood in having no striatums between 

 the ribs, in being more rotund, and showing no incurving of 

 the ribs as they approach the ventral margin. 



Claiborne, Ala., and Jackson, Miss. 



Bulla (JETaminea) Aldrichi, nov. sp.* 



Shell elongate oval, substance rather thin, punctate-striate, 

 striae about 20, transverse ; spire involute ; labrum sharp and 

 slightly dentate ; mouth longitudinal and rather larger at base 

 than at top ; columella very slightly thickened at the base. 



Height -2 Breadth -1 



Resembles B. glaphyra Desh., but differs in the striae which 

 are in B. Aldrichi from the top to the bottom, while in B. 

 glaphyra Desh. they are confined to the upper and lower thirds 

 of the shell. 



These two species will be figured in the forthcoming Report 

 of the Greological Survey of Alabama. 



Akt. XXI. — On the Area of Upper Silurian rocks near Cornwall 

 Station, eastern-central Orange Co., N. Y. • by Nelson H. 

 Darton. 



In the course of a detailed examination of the formations 

 other than Archasan in Orange Co., 1ST. Y., the writer has made 

 a careful study of the locality long known as the Townsend 

 Iron Mine, and its vicinity, where, in a limited area, a small 

 mass of Lower Helderberg limestone has been protected from 

 the general denudation by a firm backing of coarse, strongly 

 cemented sandstones ; the whole forming a hill, passing a few 

 meters west of Cornwall Station. Its more prominent geolog- 

 ical features are shown on the accompanying map. 



The occurrence of this series of fossiliferous strata, so far dis- 

 tant from the main mass of the formation to the north and 

 west was first noted by Dr. Horton in the Report of the Nat- 

 ural History Survey of New York for 1839. On page 151, in 

 a very general description there is the statement — " its apparent 

 position is between the slate and grit-rock or Millstone grit of 

 Prof. Eaton." The exact meaning of this is not entirely clear ; 

 Prof. Eaton's " Millstone grit" would in this instance be equiva- 



* Named in honor of my friend, Mr. T. H. Aldrich, of Cincinnati, Ohio. 



Am. Joue. Sci. — Third Series, Vol. XXXI, No. 183. — March, 1886. 

 14. 



