This important unsolved problem is further commented upon below. 



As above noted, the eroded Magothy surface was quite irregular and over considerable 

 areas at the western end of the island it was removed entirely. It was also deeply channeled by 

 numerous streams; the north shore bays seem to have cut into it as far back as the then 

 existing water parting near the southern ridge and to the north cutting down either to the 

 rock or to whatever level matched the easterly flowing Sound river. This particular point has 

 not yet been determined and is of importance as these ravines may have cut through all the 

 Cretaceous strata to the rock, were later filled more or less with glacial material and thus may 

 have brought the salt water of the sound practically into contact with all the Cretaceous aqui- 

 fers, as has been particularly exemplified by one of the Lloyd wells at Port Washington. It is 

 also quite probable that similar ravines once were formed further to the east, such formations 

 as Mount Sinai harbor and Wading river possibly i-epresenting the last remnants of such 

 ravines. It is well also to note that the north shore of the south fluke contains signs of similar 

 erosion — particularly Three Mile harbor and the extension thereof under Gardiners Island 

 sound. Furthermore, on the south shore, east of Babylon, there appear to be evidences of a 

 large number of deeply cut southward trending valleys which subsequently have been filled by 

 glacial material which has settled, giving rise to the basins with peculiar oak-leaf contours 

 so prevalent in Suffolk county. All of this is quite indefinite, and it should be noted that although 

 these indentations are shown by borings well inland from the south shore, the Magothy wells 

 along the bar beach are rather consistently shallower. Just what the drainage system was 

 cannot be told, but can be assumed either as draining across the bar beach between the scat- 

 tered borings or that there was a lateral valley similar to Peconic river in Great South bay and 

 extending eastward. This last sounds rather fanciful, but at least should be borne in mind as 

 additional information comes in. 



JAMECO 



This formation is stated to be the earliest of the glacial series and it is supposed that it is 

 material originating up the Hudson valley transported by the outwash from an ice cap which 

 never reached the island and to have thus been dumped in the positions now found. 



It is of considerable but unknown depth and extent in Kings county and extends well along 

 the south shore of Kings and Nassau counties. 



Many of the boundaries of the Jameco are quite indefinite ; particularly near Newtown 

 creek where it is in unexplored territory, under a moraine and anyone's guess as to where it 

 is. The well logs indicate a narrow neck extending to the north, but the top of the deposit so 

 shown does not meet the contours worked out for the underlying Raritan. By assuming it to 

 be spread out in territory where there is no information, a fairly good fit was obtained. All 

 of this is rather poorly supported guesswork. This deposit has been studied as a construction 

 problem and as such is most baffling. In western Kings it is pretty well piled up and not impos- 

 sible, but farther east it forms a sort of lining to a depression which could occur only if it 

 were poured over the edge of the depression. This would involve transportation over a fairly 

 high part of the island. It might have been so deposited as to fill the depression and subsequently 

 to have been eroded out, but this seems fanciful. 



In the Gravesend region there is a considerable hill resting on a similar hill of Magothy 

 materials. This hill in turn is capped by Gardiners. Although this hill must have resulted from 

 the erosion of the deposited strata, it is so shaped that erosion is not evident. 



All this must remain a puzzle until more evidence comes in. 



This formation has not been identified elsewhere in the island but it may occur and on 

 account of changed source of origin it may not have been readily identified. 



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