PLEISTOCENE GEOLOGY OF NASSAU CO. AND BOROUGH OF QUEENS 64:9 



angle rarely as steep as that of repose of sliding materials on an 

 ancient cliff whose base has been abandoned by the sea. One such 

 steep place a few yards in length occurs between Jamaica and 

 Ilollis. 



Along the base of the slope at the inner edge of the plain, 

 if wave action had determined the lineality of the morainal front 

 and secondarily its slope, there is a lack of the critical evidence 

 which one would expect to find at the place. The generally 

 unstratified character of the deposit forming the morainal front 

 offers little evidence as to whether it has been cut back by wave 

 action or not, but on the west side of Prospect park in Brooklyn 

 decisive evidence on this point is found. 



West of Prospect park the morainal front maintains its lineal 

 course toward Xew York narrows, but with a rather bulging 

 frontal slope composed of stratified gravels. As seen in pits open 

 in the season of 1900, these stratified gravels rise up steeply from 

 the northern margin of the frontal plain, then bend downward into 

 a large kettle-hole in tlie deposit, a c^.epression marking the site of a 

 mass of ice. The attitude of the beds suggests frontal shoving on 

 the part of the ice sheet as well as irregular deposition ; but the 

 significant feature at this locality is the apparent absence of any- 

 thing like a cut bench or cliff in the bulging front of the deposit. 



The structure of the sand plain is exposed in occasional pits. 

 The beds are prevailingly cross-bedded, showing frequent reversals 

 in direction of the transportation of the sediments. Such cross- 

 bedded layers occur in glacial gravels where there is no reason for 

 supposing the sea to have acted on them. 



On the east, on the Oyster Bay sheet, the inner margin of this 

 frontal plain rises above the 100 foot contour level ; in this region 

 it sinks gradually below it, till north of the Jamaica bay depression, 

 where the plain has a width not exceeding 1|- miles above sealevel, 

 its bight next the moraine is only 60 feet ; westward it rises slightly 

 again. For a portion of its length, therefore, this line accords in 

 elevation with the 80 foot level of the water body in which the 

 Port AYashington delta was built. If througliout the line accorded 

 with the Port AYashington level, it would favor the existence at 

 that stage of a body of water in front of as well as in the rear of 



