360 Geology of Long Island. 



from Huntington Bay we have the Dix Hills and Comae Hills 

 rising about 250 feet. Southeast of Smith town Harbor, we have 

 Mt. Pleasant, 200 feet in height ; in a like direction from Stony 

 Brook Harbor, are the Bald Hills, also 200 feet high. Again 

 we have Beulands Hill, which is 340 feet in height, and has the 

 seme general bearing from Port Jefferson Harbor. About South 

 30° East from Wading Kiver, where there is quite a deep valley, 

 we find Terry's Hill, 175 feet high. South of Great Peconic 

 Bay rise the Shinnecock Hills, 140 feet, and southeasterly from 

 Little Peconic Bay are the Pine Hills about 200 feet high. From 

 these instances it will be seen that the areas of high elevation 

 bear a very marked geographical relation to the deep indentations 

 of the coast. That this relation is due to glacial action, seems 

 more than probable, as it can scarcely be an accidental coinci- 

 dence that the highest hills on the island should be in a line with 

 the deepest bays on the northern coast, and that the course of 

 these bays should coincide with that of the glacier. 



At every point along the north shore where a section of the 

 strata is exposed, the flexed structure of the beds under the drift 

 may be observed. On Gardiner's Island, these folds are remark- 

 ably prominent, the surface of the island being broken with nu- 

 merous parallel ridges having a general trend N. 65° E. These 

 ridges correspond to folds in the stratified beds, which the sur- 

 face drift overlies unconformably, and as they are at right angles 

 to the line of glacial advance it is difficult to conceive any agency 

 which could have produced them except the lateral thrust of the 

 ice-sheet, Unless these phenomena can be referred satisfactorily 

 to some other cause, and of this I very much doubt the possi- 

 bility, we have in these folds a strong argument against the ice- 

 berg theory, as it seems evident that a mere drifting berg could 

 not develop sufficient progressive force to do the work here 

 shown. A similar origin may be attributed to the ranges of 

 hills which form the so-called "back-bone" of the island; as 

 their structure indicates that they have been formed partly of 

 gravel and sand transported from the north shore, and partly 

 through the upheaval of the stratified beds by the friction of the 

 moving mass of ice. As the downward pressure of the glacier was 

 about 450 lbs. per square inch for 1,000 feet of thickness, and its 

 progressive force was only limited by the resistance of the ice, it 



