GEOLOGICAL DISCUSSION. 27 



This clay deposit is somewhat different in coloring and texture from that of any other 

 locality, and for that reason I have thought it possible that it might represent a 

 distinct geologic horizon. It is, however, more or less involved with the overlying 

 moraine and the adjacent sandy clays of the Weyquosque series, so that its exact 

 stratigraphic position is uncertain, and, unfortunately, the plants collected are few in 

 number and are largely of uncertain identity. Of the 222 species described in this 

 monograph only 13 are listed from this locality, and of these four are only pro- 

 visionally identified and two others are described as new. 



At Gay Head fossil plants occur in certain of the gray sandy clays and in the fer- 

 ruginous nodules and concretions, either in place or scattered in the talus accumula- 

 tions of the escarpment. The stratigraphic relations of the various beds represented 

 in this section are too uncertain for definite conclusions on account of the tilting and 

 distortion to which they have been subjected; but inasmuch as 103 species of fossil 

 plants — a large majority of them representing well-known Cretaceous types — have 

 been identified from this locality alone, the age of the beds from which they came 

 can not be questioned. Both the Raritan and the Cliff wood formations are repre- 

 sented in these species. 



On Block Island, at all the localities, the fossils were found only as morainal 

 material, in ferruginous shale or sandstone, but mostly in close association with 

 transported or eroded masses of plastic and lignitic clay. No organic remains of 

 any kind, other than the lignite, have been found in these clays; but their lithologic 

 characters and the close association with them of the characteristic ferruginous 

 material containing Cretaceous leaves are strong presumptive evidence of their age, 

 especially as they lie directly on the line of strike between the clays of Marthas 

 Vineyard on the east and those of Long Island on the west. 



On Long Island the localities where Cretaceous fossil plants have been found 

 are scattered throughout the hills from Montauk Point to Brooklyn. At most of 

 these localities the plants occur in the moraine, and careful investigation would 

 undoubtedly result in making known a number of others, so as to include practi- 

 cally the entire morainal area. 



On Little Neck, in Northport Harbor, and at Cold Spring, impressions of 

 leaves occur in the clays, while at Glen Cove numerous specimens have been found 

 in a layer of ferruginous shale, interbedded with the clays. This shale is more or 

 less fractured and slickensided, apparently representing a fault line or shear plane 

 in the clay, along which atmospheric waters percolated, oxidizing the iron in the 

 clay and transforming it into a thin layer of ferruginous shale along the line of 

 fracture. At this locality the clays are not only disturbed as a whole and more or 

 less tilted, but they are also locally disturbed by landslips, the effects of which may 

 be seen in the changes which take place from year to year on the face and at the 

 base of the bluff. Next to the Gay Head exposure this is the locality which has 

 yielded the greatest number of fossil plants. They occur in the layer of shale above 

 mentioned, and also in the fragments which have been eroded from the exposure 

 and scattered along the beach. 



At Sea Cliff, near Mott Point on Manhassett Neck, and at Elm Point on Great 

 Neck, clays are exposed, but no fossil leaves have been found in them. At the 

 locality first mentioned the matrix in which the leaf impressions occur is exactly 



