480. PROCEEDINGS OP BALTIMORE MEETING. 



Shortly after highly fossiliferous strata were found by the writer * in Anne Arundel 

 and Prince Georges counties, Maryland, and described in 1889 as the equivalent of 

 the lower greensand beds. A further account of the same deposits was published 

 a little later by Uhler.f In 1890 Darton J gave the general name of Severn forma- 

 tion to these strata. It is now known that an extensive series of greensands, also 

 of Cretaceous age, is found above the Severn. 



In the state of New Jersey the Cretaceous has long been a subject of investiga- 

 tion, a classification being proposed by the late Professor Cook, which with some 

 important modifications and the substitution of place names, has been adopted by 

 the writer. 



The Formations 



CLASSIFICATION 



The classification proposed in an earlier publication for the Cretaceous strata in 

 eastern New Jersey is as follows : § 



Formations. Economic equivalents. 



Manasquan = Upper marl bed (lower part). 



Rancocas =: Middle marl bed. 



Redbank — Red sand. 



Navesink =- Lower marl bed. 



Matawan = Clay marls. 



Raritan = Plastic clay. 



DISTRIBUTION 



With the exception of the Rancocas formation, which receives its name from an 

 important creek in Burlington county. New Jersey, all the other divisions of the 

 Cretaceous have been named from typical localities in Monmouth county. Although 

 the terms employed have thus been taken from local areas in the extreme northern 

 portion of the district, the formations have an extremely persistent character and 

 wide range. In the case of the lower divisions, representatives are found extending 

 throughout New Jersey, Delaware and Maryland, reaching from Raritan bay to 

 the Potomac river, while the upper divisions are often buried beneath the later 

 deposits which, unconformably overlie them. 



RARITAN FORMATION 



The Raritan consists of alternating beds of sand and clay, which change in 

 thickness and texture so rapidly that no section is typical except within narrow 

 limits. The strata extend across central New Jersey and thence, bordering the 

 Delaware, river on both its Pennsylvania and New Jersey banks, are continued in 

 the Potomac formation of Maryland and more southern latitudes. 



The evidence of paleobotany seems to point to a later phase of deposition in the 

 , Raritan than in the Potomac, but it is probable that they are largely of similar age 

 and origin. More extended study of the flora is important for the final determina- 

 tion of this point, and geologists are greatly indebted to Professor Lester F. Ward 



* Johns Hopkins University Circular, no. 69, pp. 20, 21. 

 t Trans. Maryland Acad.Sci., vol. i, pp. 11-32. 

 X Bull. Geol. Soc. Am,, vol. 2, pp. 438, 439, 

 g Journal of Geology, vol. ii, pp. 161-177. 



