774 



SCIENCE. 



[N. S. Vol. XIV. No. 359. 



in. All below this and all fiber not vein fiber 

 goes to the mill and is mechanically separated, 

 as the third grade. In the Vermont localities 

 the slip fiber is exposed on the property of the 

 New England Co., and of its neighbor, the 

 American Co. The vein fiber is limited, so far 

 as yet opened up, to the property of Mr. M. E. 

 Tucker and associates. 



It is difiicult, with the data in hand, which 

 were gathered under the direction of Dr. C. W. 

 Hayes, of the U. S. Geological Survey, to trace 

 the geological history of the serpentine, but it 

 must have been originally either an igneous 

 pyroxenite or peridotite or else a richly mag- 

 nesian siliceous limestone. There are such 

 slight traces of calcium-bearing minerals, how- 

 ever, that the former supposition has the greater 

 weight. The hornblende-schist consists in 

 largest part of common green hornblende but 

 one may also observe epidote, zoisite and some 

 minor accessories. 



Professor Kemp also gave a paper on the 

 ' Physiography of Lake George. ' The observa- 

 tions, extending over several years, have sug- 

 gested the following conclusions : Lake George 

 occupies a submerged valley very similar to 

 many others in the Adirondacks which are not 

 submerged. The valley has been largely pro- 

 duced by faulting, and the fault-scarps still 

 remain in precipitous cliffs, whose sharpness has 

 not been much affected by weathering and ero- 

 sion. Before the Pleistocene the valley was prob- 

 ably a low pass with both a north and a south dis- 

 charge. 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 Katts- 

 kill 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 very 

 depresse4 Trout brook valley, just west of 

 Rogers Rock and Cook mountains. Trout 

 brook is now as much as a hundred feet lower 

 than Lake George at points south of the Ticon- 

 deroga 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 here 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 valley to the west 

 makes this the natural outlet, and there is reason 

 to believe from the general topography that the 

 discharge passed north into the Champlain val- 

 ley near the south boundary of Crown Point. 

 It is also not to be overlooked that a valley 

 with much drift leads eastward to Lake Cham- 

 plain, 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 80 feet above the present level of the lake. 

 These are best developed on Indian Kettles 

 Point, about two miles north of Hague. They 

 were doubtless excavated by lateral or sub- 

 glacial streams when the ice filled the lake val- 

 ley, because in no other conceivable way could 

 flowing water be forced into such unnatural 

 situations. 



There is great need of a good hydrographic 

 survey of the lake, and of detailed pilot charts, 

 with soundings. They would be of great ser- 

 vice, not alone to navigators, but to science as 

 well. So far as could be learned from local 

 fishermen, whose deep trolling for lake trout 

 gives them familiarity with the bottom, there 

 appear to be channels whose general trend is 

 parallel with the long dimension of the lake, 

 and which have precipitous sides, precisely like 

 the valleys and gulches now visible. The lake 

 is relatively shallow as compared with Lake 

 Champlain. In Lake George, the greatest 

 depth is believed to be near Anthony's Nose, 

 and to reach 190 feet. Elsewhere the deep 

 parts are placed at about 100 feet, more or less. 

 All this, however, requires confirmation by 

 soundings. With regard to the physiography 

 of the bottom one cannot say to what extent 

 the valley has been filled by drift, but the 

 islands to which physiographic importance has 

 here been given are rock. 



Richard E. Dodge, 

 Secretary pro tem. 



