1898.] NATURAL SCIENCES OF PHILADELPHIA. 425 



and vicinity has been found by the writer in the Norfolk well bor- 

 ing at between the depths of 585 and 625 feet, while the continuation 

 upward of the same clay contained sponge spicules up to about 400 

 feet from the surface. No diatoms or sponge spicules were found 

 higher in this well excepting between the depths of 25 feet and 65< 

 feet, where a stratum, probably the equivalent of the Dismal Swamp 

 bed, contained these same micro-organisms, though, as in the Dis- 

 mal Swamp deposit, very sparingly. The Miocene beds at Bermuda 

 Hundred and Petersburg are rich in diatoms, and especially so ii* 

 A. Heliopelta, and since the diatoms in the Dismal Swamp deposit 

 were exceedingly meager, (perhaps not one per cent, of the entire 

 matrix), and since A. Heliopelta and other Miocene species were 

 scantiest in numbers of all the contained forms, we cannot, in view of 

 all the facts, consider that the introduction of these Miocene forms has 

 been by other than mechanical means in post-Miocene times. At what 

 period that subsequent time was, three of the more recent forms, 

 Campy lodiscus Echenels, Cerataulus turgidus and Stauroneis Phoeni- 

 eenteron, shed much light. We will now particularly notice each of 

 these forms. 



In a mass of brick clay from a low terrace at Bridgeton, N. J., 

 which terrace is assigned by the New Jersey State Geological 

 Survey report to a very recent geological phase of the gravels of 

 that State, the writer found a very considerable number of diatoms 

 not at all Miocene in aspect, and among them a large number of 

 the same species of Cerataulus. 



Respecting Campylo discus Eeheneis it may be stated that this form 

 has been recorded as living principally in brackish waters the world 

 over, though Prof. C. S. Boyer informs the writer that he has found 

 it in a fresh water reservoir at Philadelphia, supplied from the 

 Schuylkill River. Though not, however, heretofore recorded, so far 

 as we are able to learn, as fossil, yet the writer has so seen it in a 

 low level clay from near Buckskutem on the Maurice River, below 

 Millville, N. J., the stratigraphical position of which is the equiva- 

 lent of the Bridgeton clay above referred to. 



On a map of the surface formations of New Jersey in the annual' 

 report of the geological survey of that State for 1897 there is shown- 

 a low level formation on the shores of Raritan Bay and thence border- 

 ing the Atlantic Ocean from Sandy Hook to the Cape May peninsula,, 

 which it either entirely covers or nearly so, and thence extending 

 up the Delaware River nearly to Trenton. This low lying terrace, 



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