REPORT OF THE STATE PALEONTOLOGIST I903 I9I 



mostly deposited. It would, therefore, be expected that the larger 

 shells would not be found in the very deep waters i. e. below the 

 depths at which marine algae flourish. This theory is supported by 

 the work of Agassiz while associated with the dredging steamer 

 Blake.^ In discussing Gastropods and Pelecypods, he thus con- 

 cludes, " Deep sea dredging has thus afforded few specimens of even 

 moderately large size, judged by the standard of shallow water or 

 littoral shells." 



It thus seems well to look on the fauna of these upper Oriskany 

 beds as existing in deeper portions of the sea at the same time that 

 the typical Oriskany Falls fauna lived in comparatively shallow 

 waters. Yet this deeper portion was not removed beyond the reach 

 of land-derived sediment for the beds are more or less argillaceous 

 and silicious limestones. 



All the large fossils of the original Oriskany noted above as prac- 

 tically absent from the Port Jervis region, are very abundant at 

 Becraft mountain^ and also, with the exception of C a m a r o - 

 toechia barrandei, near Rondout N. Y.^ But they are 

 likewise associated in these regions with many Helderbergian forms. 

 The practical absence of these fossils from the Port Jervis region 

 can not be due to insufficient time for the migration of the species 

 into this region, as they occur both south in Maryland, with also 

 many in Pennsylvania, as well as north in New York State. Nor 

 can it be due to some barrier since many typical Oriskany forms 

 occur here. It may possibly be due to a greater depth of water. 



Oriskany-Esopus szvainp 



This swamp probably rests on the upper beds of the Oriskany, 

 being worn out of the more easily disintegrated Esopus. The pre- 

 glacial drainage having been obstructed, this has been filled in to a 

 depth of probably 20 or 30 feet in places. It is interesting to note 

 that on Becraft mountain, also, " the contact between the Oriskany 



^Agassiz, Alexander. Three Cruises of the U. S. Steamer Blake, 2:62. 



^Clarke, J. M. Oriskany Fauna of Becraft Mountain. N. Y. State Mus. 

 Mem. 3, p.67. 



'van Ingen & Clark, P. E. Disturbed Fossiliferous Rocks in the Vicinity 

 of Rondout, N. Y. N. Y. State Paleontol. An. Rep't. 1902. p. 1203. 



