110 J. D. Dana on the origin of some of the 



at a depth of 68 feet, or about 60 feet below mean-tide level. The 

 boring passed through dQ feet of harbor mud, and, below this, through 

 sea-shore or worn sand, which was coarser below. The great depth to 

 water at a point so far inside of the Trowbridge and Staples wells, and 

 also the thickness of the deposit of mud, are accounted for by the 

 fact that the place was just within the mouth of the East Creek 

 estuary. 



[It may be added here, although not exactly relevant, that an arte- 

 sian boring by Mr. Kilburn in Howard street, opposite McLagon & 

 Stevens's factory, descended through 60 feet of quicksand, and struck 

 the solid sandstone rock at a depth of 68 feet. The sandstone was 

 that of the underground slopes of Sachem's ridge.] 



I. In Greene street, at the India Rubber Works, about 50 rods above 

 the Gas Works, an artesian well was sunk, under the direction of Mr. 

 H. Hotchkiss, to a depth of 250 feet. But the existence of a hard 

 layer was not noted, and is uncertain. The material passed through 

 was mainly like that of the plain for 1 40 feet ; then followed a bed of 

 "splendid" clay, 14 feet thick; and below this the same essentially 

 as above. At the bottom the tubing was badly bent by striking 

 against something supposed to be rock, and the boring was conse- 

 qiiently suspended. It is not known whether the rock was solid sand- 

 stone or a loose mass. 



1. The facts show that a hard layer, called hard-pan, may be reach- 

 ed beneath the harbor, and the estuary part of the Quinnipiac and 

 West Rivers, at depths mostly between 30 and 45 feet; that its 

 depth along the north side of the deep-water channel of the bay is 40 

 to 45 feet; that this continues to be its depth through nearly two- 

 thirds of the line of the Canal railroad wharf (which is much farther 

 shoreward than along that of Long Wharf, owing to the fact that 

 Long Wharf was built out as the extension of a sandy point between 

 East and West Creeks, while the new wharf is situated off the mouth 

 of East Creek) ; that toward the shore the depth of the hai"d-pan gen- 

 erally decreases. 



2. That the hard-pan is one of the layers of the stratified drift, 

 that is, of that portion of the drift which was deposited over the bot- 

 tom of the bay and rivers. 



3. That the layer varies in thickness ; that it may generally be pen- 

 etrated by a continued driving of a pile ; and when passed, the pile 

 goes easily through a great depth of material before another hard 

 layer is found ; and that this soft material beneath the first hard-pan 



