RECORDS Ul 



sists of common green hornblende and of an unusual amount 

 of titanite, there being little less than those two present. 



Physiography of Lake George. — Observations extending over 

 several years have suggested the following conclusions. Lake 

 George occupies a submerged valley ver\' similar to many others 

 in the Adirondacks, which are not submerged. The valley has 

 been largely produced by faulting, and the fault-scarps still re- 

 main in precipitous clifts, whose sharpness has not been much 

 affected by weathering and erosion. Before the Pleistocene, the 

 valley was probably a low pass with both a north and a south 

 discharge. The portion rich in islands near Pearl Point, and the 

 Hundred Island House, was probably the divide, and the islands 

 represent the old hillocks near the top of the divide. At the 

 south the water is backed up by sands and morainal matter in 

 the valleys on each side of French ^Mountain, viz., at the head 

 of Kattskill Bay, and at Caldwell. On the north they are held 

 in by Champlain clays and syenitic gneiss at the Ticonderoga 

 outlet, and probably by morainal material at the low pass just 

 south of Rogers Rock and leading out to the ven,' depressed 

 Trout brook valley, just west of Rogers Rock and Cook Moun- 

 tains. Trout brook is now as much as a hundred feet lower than 

 Lake George at points south of the Ticonderoga barrier. The 

 northern barrier is rock because the Ticonderoga river passes 

 through a narrow and shallow channel in the exposed ledges a 

 mile south of its actual first waterfall. There is a broad flat 

 valley buried in clays, however, beneath which an old channel 

 may lie submerged. At the same time, the marked depth of 

 the Trout brook vallev to the west makes this the natural out- 

 let and there is reason to believe from the general topography 

 that the discharge passed north into the Champlain valley near 

 the south boundary of Crown Point. It is also not to be over- 

 looked that a valley with much drift leads eastward to Lake 

 Champlain, from the head of Mason's Bay. 



A curious feature that is common to both shores of the lake 

 north of Sabbath Day point (and perhaps also south of it), is 

 the presence of pot holes of great perfection and as high at times 

 as 30 feet above the present level of the lake. These are best 



