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TRANSACTIONS OF THE 



possible to classify the species from these organs, viewed 

 separately, those of the upper and lower jaw being in 

 most instances entirely different in form. The cabinet 

 of the Academy of Natural Sciences, however, contains 

 specimens of sharks' teeth from New Jersey " marl 

 pits," which resemble closely those of the Squalus 

 zygena, S. mustelus, S. squatina and S. carcharias, 

 two specimens of the last measuring five inches in length 

 and four broad at base. Provided the same proportion 

 exists between the fossil and recent Carcharias, the 

 former must have been more than forty feet in length. 

 Parkinson's Organic Remains, vol. iii., contains good 

 figures of the teeth of most of the above named species ; 

 also, Mantell's Geology of the South East of England, 

 p. 132. For further observations on the fossil remains 

 of sharks, vid. " Journ. Acad. Nat. Science of Philad." 

 vol. iv. p. 232, pi. xiv., in an essay published by the 

 author, entitled " Notice of the Plesiosaurus, and other 

 fossil reliquise, from the state of New Jersey, 1824." 



Professor Hitchcock, in his u Report of the Geology 

 &c. of Massachusetts," p. 193, pi. xi. and xii. has given 

 figures of fossil teeth and vertebra, found in what he 

 terms the plastic clay formation at Gay-head, Martha's 

 Vineyard ; the former are evidently the remains of 

 sharks, similar to those found in the green sand of New 

 Jersey, the latter are either not well figured, or resem- 

 ble but indifferently the vertebrse of sharks ; but possi- 

 bly the statement of the author, that " in general they 

 (the bones) are much broken and often rolled," will ex- 

 plain their anomalous forms. 



