94 



HOLLICK. 



Throughout the plain region, however, it is invariably found 

 to consist of a core of contorted Cretaceous clays and Tertiary 

 gravels, on top of which is the true morainal material. This 

 structure is the same throughout Long Island, Block Island 

 and Martha's Vineyard and is manifestly the result of ice ac- 

 tion, first squeezing upward and pushing forward the incoherent 

 strata of the coastal plain, afterwards melting and depositing the 

 glacial debris on the ridge thus formed. 



Character of the Material. 



The morainal constituents comprise practically all rocks which 

 outcrop between Staten Island and the Adirondacks. The 

 boulders most abundantly represented are of diabase, evidently 

 derived from the Newark system of New Jersey, while the bulk 

 of the finer material which enters into the composition of the 

 till is Triassic shale or sandstone, giving to it a prevailing red 

 color. A large number of other boulders have been more or 

 less definitely identified from their lithological characters, but by 

 far the most satisfactory determinations have been made from 

 those in which fossils were found. 



Lists of Fossils. 



Two lists of these fossils have been prepared. The first con- 

 tains 1 1 2 Palaeozoic species, the second 42 Mesozoic species. 



I. Paleozoic Fossils found in the Drift on Staten Island. 







GEOLOGICAL 







NAME. 



HORIZON. 



LOCALITY. 



I. 



Ambony cilia radiata Hall. 



Hudson ( Lorraine ) 



Kreischerville. 



2. 



Anoplia nucleata (Hall). 



Oriskany. 



Clifton. 



3- 



Anoplotheca concava (Hall). 



Lower Helderberg. 



Clifton. 



4- 



flabellites(Hall). 



Oriskany. 



f Chfton. 

 \ Tottenville. 



5- 



Aspidocrinus scutelliformis Hall. 



Lower Helderberg. 



Prince's Bay. 



6. 



Atrypa reticularis Linn. 



J Schoharie. 



\ Lower Helderberg. 



Prince's Bay. 

 New Brighton. 



7- 



" " impressa Hall. 



Schoharie. 



New Brighton. 



8. 



Atrypina imbricata Hall. 



Lower Helderberg. 



Clifton. 



9- 



Aviculopecten recticostus Hall. 



Oriskany. 



Clifton. 



10. 



" umbonatus Hall. 



Lower Helderberg. 



Prince's Bay. 



