418 HO LUCK. 



moraine, has led me to think that they are not characteristic of 

 the series except as representing fragments of clay strata which 

 were originally in a plastic condition but which have become 

 hardened by oxidation after having been torn up and made part 

 of the morainal material. This view is further strengthened by 

 the fact that these concretions and fragments may be found in 

 the moraine in every stage of development from masses of soft 

 clay with only a thin shell of limonite on the outside to those 

 which are hardened throughout. Many of the hardest frag- 

 ments also exhibit beautifully defined planes of shearing or 

 slipping, evidently accomplished before the process of harden- 

 ing had been completed. In several localities, notably at Glen 

 Cove, Long Island, and at Gay Head, Martha's Vineyard, the 

 shaly fragments and concretions occur in the Cretaceous clay 

 strata, but these strata are greatly contorted and have been sub- 

 jected to similar conditions to those which have wrought the 

 changes noted in the mixed morainal material. The disturbance 

 of the strata would naturally expose them to the same oxidizing 

 influences and would cause portions of them to be converted 

 into hardened seams or assist in the formation of concretions. 

 So that until we find the strata upon the mainland with such 

 hardened seams, fragments or concretions in place and con- 

 taining representatives of the same flora, the most reasonable 

 explanation of their occurrence throughout the morainal region 

 of the islands would seem to be that it is due to oxidation 

 caused by the disturbance wrought there by glacial action. 



Cretaceous Plants of Staten Island. 



In the following list Nos. 4, 5, 8, 9, 10, 11, 12, 14, 15 and 

 16 have not before been reported from Staten Island, and No. 

 1 2 represents a species here described for the first time. 



I. Moriconia cyclotoxon Deb. & Ett. 



(Plate XXXVII, Pig. 8.) 



Moriconia cyclotoxon Deb. & Ett., Urwelt. Acrob. Kreidegeb. 

 Aachen und Maestricht, p. 59 (239), PL VII, P'igs. 23-27. 

 Locality : Prince's Bay, Staten Island. 



