IX 



Firstly, we have a geologic flora ; and secondly, we have a residual 

 flora which, during the six thousand to ten thousand years spoken of, 

 was gradually forced northward by the sea and the subsidence and 

 gradually encroached upon from the north by the third flora, consist- 

 ing of plants which had come from the north before the ice sheet. 



L Geological Flora ; Old Cretaceous Flora. 



It is beyond the purpose of the present writer to discuss in full the 

 occurrence of Cretaceous plants on Long Island. That they are found 

 there has been definitely proven by Dr. A. Hollick.^ 



A brief glance at the maps of the coast from Cape Cod southward 

 reveals, if one looks at the contours that have been made by soundings, 

 that for a space of seventy-five miles from the coast there is a gradual 

 •drop about on a line with the general slope of the hills above the 

 water. At the hundred -fathom limit, however, there is a sudden and 

 immense drop of the water ; it is seen that here is to be found the old 

 Tertiary continental coast line that existed before the advance of the 

 glacier from the north. The gradual submergence of the whole 

 eastern portion of the continent has proceeded until now the only por- 

 tion exposed of the continent of this part of North America that ex- 

 ist^ in the Tertiary times is found along the narrow belt of land lying 

 at the base of the glacial drift, and, as before quoted, certain out-crops 

 in New Jersey, certain portions in Long Island and underlying de- 

 posits of glacial drift of varying thickness in the islands stretching' to- 

 ward Cape Cod. This has been so well shown by Dr. A. Hollick that I 

 cannot refrain from repeating his exact words. — ^^ From a study of the 

 existing geological and floral additions, as I have elsewhere attempted 

 to demonstrate, the indications are that at the close of the Ice Age 

 there was a continuous strip of land, except for certain river outlets, 

 extending from what is now New Jersey to the southeastern New 

 England coast, with a large body of fresh water occupying the deepest 

 parts of what is now the basin of Long Island Sound. This strip con- 

 sisted of an elevated portion along the northern border, formed by the 

 terminal moraine left behind on the final retreat of the ice, and a 

 plain region to the south, of varying width, representing what re- 

 mained of the old Tertiary coastal plain, which formerly extended out 

 to what is now the one hundred fathom contour. ' ' 



I here append a list of the Cretaceous fossils found on Long 

 Island as given by A. Hollick. f 



*• Plant Distribution as a factor in the Interpretation of Geological Phenomena, 

 Trans*. N, Y. Acad. Sciences, Vol. XIL 



fSome Further Notes on the Geology of the North Shoie of Long Island with 

 their Distribution. 



