100 HOLLICK. 



of rock, which could be even provisionally identified as Cre- 

 taceous in age, has been found there. 



The character of this Cretaceous material is identical with that 

 which is found in connection with the moraine throughout Long 

 Island and the islands to the eastward, consisting of ferruginous 

 shaly fragments, or concretionary nodules of hardened clay or 

 marl, due to oxidation of the included iron salts or to the forma- 

 tion of limonite layers over the exterior. The lithologic char- 

 acter of this material, even in the absence of any palaeontologic 

 evidence, is so peculiar that once recognized it can not be mis- 

 taken for anything else. It evidently represents fragments of 

 clay or marl which have been torn up and included in the moraine, 

 after which it became oxidized and hardened into the condition 

 in which we now find it. 



Attention should also be called to the significance of the oc- 

 currence of marl fossils at Clifton, indicating beyond doubt that 

 the marl belt, which now has its farthest eastward exposure in 

 New Jersey, at the Atlantic Highlands, must originally have ex- 

 tended across the Lower Bay to Staten Island and occupied part 

 of what is now New York Harbor. This fact gives us the con- 

 necting link between what we know of the outcrop of New Jersey 

 and what we infer in regard to its eastern extension, from the oc- 

 currence of similar fossils in the moraine of Brooklyn, Montauk 

 Point, Block Island and Martha's Vineyard. Thus far, how- 

 ever, no exposure of marl strata has been found on Staten 

 Island. 



Finally, it is of interest to note the relation which the mo- 

 raine bears to the underlying or pre-glacial topography. Appar- 

 ently the serpentine ridge served as a more or less effective 

 barrier to the advance of the ice, as indicated by the mo- 

 rainal sinus immediately south of the highest point of the ridge, 

 from whence the ice was deflected eastward towards Fort Wads- 

 worth and southward toward Prince's Bay, forming the lobes in 

 the moraine at those localities and protecting the plain region 

 between by checking the further advance of the ice in that 

 direction. 



Columbia University, 

 October, 1898. 



