746 INDEX TO THE STEATIGRAPHY OF NORTH AMERICA. 



The following scheme of classification has been proposed for the New Jersey formations: 



Miorpnp jCohansey sand and Beacon Hill formation. 



I Kirkwood formation. 

 Eocene Shark River marl. 



The Shark River, which is limited to a small area in eastern New Jersey, consists of green- 

 sand marls and apparently overlies the Manasquan formation of the Upper Cretaceous con- 

 form,ably. The deposits are about 12 feet in thickness. The fossils are marine invertebrates of 

 lower Eocene age. 



The Kirkwood formation consists of sands and clays which unconformably overlie the 

 older deposits of Eocene and Cretaceous age. It has a thickness of about 100 feet and contains 

 in places a considerable fauna of marine invertebrates similar to the Calvert fauna of Maryland 

 and Virginia. 



The Cohansey consists chiefly of buff sands, although sandy clays and coarse white sands 

 are also found. It has a thickness of about 100 feet. No diagnostic fossils have been found. 



The Beacon Hill formation consists of gravel and sand and probably represents the shore- 

 ward phase of the Cohansey sand in the northern part of the New Jersey Coastal Plain. It 

 has a maximum thickness of about 40 feet. No fossils have been found. 



The deep well borings near the coast have penetrated several hundred feet of characteristic 

 Miocene sediments in which fossils that apparently represent the Calvert, Choptank, and St. 

 Marys faunas of Maryland and Virginia are found. It is apparent that the Kirkwood forma- 

 tion represents the Calvert formation, but whether the Cohansey sand and the Beacon Hill 

 formation should be regarded as Choptank, which they resemble lithologically, is impossible 

 of determination in the absence of characteristic fossils. It has been suggested that the Cohansey 

 and Beacon Hill may perhaps overlie all the Miocene formations of the Chesapeake region. 



Maryland and Delaware. — An extensive series of Tertiary deposits is found in Maryland 

 and Delaware, including representatives of the Eocene, of the Miocene, and probably of the 

 Pliocene. All the deposits, except the Pliocene, are highly fossiliferous and have been investi- 

 gated by many students of geology and paleontology. Among those who have studied the 

 region may be mentioned Say,'"'^ Conrad,!'^ Harris,*"" McGee,^'^^ ^^^ Clark,""- i^" Martin,"" 

 Shattuck,^'^-'" and Miller.^"^'^"' 



The following scheme of classification has been adopted for the Maryland and Delaware 

 Tertiary formations: 



Pliocene (?) Lafayette formation. 



Miocene Chesapeake group: 



St. Marys formation. 

 Choptank formation. 

 Calvert formation: 



Plum Point marl member. 



Fairhaven diatomaceous earth member. 



Eocene Pamunkey group : 



Nanjemoy formation: 



Woodstock greensand marl member. 

 Potapaco clay member. 

 Aquia formation: 



Paspotansa greensand marl member. 

 Piscataway indurated marl member. 



The Aquia formation consists chiefly of greensands and greensand marls, in places highly 

 calcareous and here and there argillaceous. These beds overlie the earlier deposits unconform- 

 ably. The total thickness of the formation is about 100 feet. The Aquia formation has been 

 divided into the Piscataway and Paspotansa members. The deposits contain a rich fauna of 

 lower Eocene age. The formation is transgressed by the Calvert formation toward the north 

 and disappears near the Maryland-Delaware line. 



The Nanjemoy formation consists of greensands, in many places highly argillaceous but 

 loss commonly calcareous than the Aquia formation, which it overhes conformably. The 



