298 H. L. FAIRCHILD POST-GLACIAL SUBMERGENCE OF LONG ISLAND 



The southern limit of the kettles is shown on the map by the line that 

 touches the south edge of the Shinnecock Hills and the sharp moraine 

 north of East Qiiogue. 



What is the explanation of these kettle plains? Ice-blocks of size 

 sufficient to produce the kettles could not be transported by subaerial 

 glacial outwash. If rafted out into standing water they could not sink 

 and be buried. The kettles must represent drift-anchored ice-blocks 

 which mark advanced positions of the ice-margin. The ice-blocks were 

 buried in drift which was leveled before the blocks melted. 



The kettles certainly represent morainic conditions. If the moraine 

 was built in the air, as required under the theory of elevation for the 

 island, then why do the kettle areas not have morainal topography? 

 Either the moraines of the kettle areas were deposited under water or 

 the land was carried down and wave-leveled and then lifted out again 

 before the ice-blocks melted. A brief discussion of the mechanics of 

 kettle formation has been given in paper number 28, pages 232-233, in 

 which it was argued that larger ice-blocks deeply buried probably would 

 not melt until the locality was exposed to the atmosphere. 



It should be noted that all the areas of kettle plains, like the smoothed 

 moraines, lie beneath the theoretic plane of marine submergence. 



STRATIFIED SANDS CONTAININa BOULDERS 



An interesting feature and another proof of submergence is the occur- 

 rence within the moraines of fine, stratified sand with included boulders. 

 The writer has observed this only in the heart of the moraine northwest 

 of Bridgehampton, but similar phenomena are likely to occur in other 

 places. About two miles northwest of Bridgehampton, and about one- 

 half mile beyond the house of Mr. William D. Halsey, is a basin or kettle 

 in the low valley which intersects the moraine. At altitude of about 140 

 or 145 feet, by the roadside, is fine sand with included ice-rafted boulders. 

 The locality is 15 or 20 feet beneath the marine plane. The deposit can 

 not be attributed to glacial waters or pools within the moraine because 

 the valley opens freely southward. The fineness of the sand rules out the 

 idea of stream-work or outwash, and the inclusion of boulders indicates 

 some depth of water for the floating ice. The marine plane has here 

 about 160 feet altitude, and two valleys which traverse the moraine were 

 swept by the sea. 



Such phenomena should be expected in the secluded, sheltered valleys 

 of the moraines. Under the conception of subaerial deposition of the 

 sands they would probably be attributed to glacial waters. 



