90 



SCIENCE. 



[N. S. Vol. XII. No. 290. 



east, but one exposure has been met in 

 Clinton County and that is a stratum about 

 20 feet thick and 150 feet long at the foot 

 of Catamount mountain. Dip and strike 

 are very difficult to determine with accu- 

 racy. The bed apparently passes into the 

 mountain at an angle of about 45-60 de- 

 grees. The relations will, however, be more 

 fully commented on in taking up the strati- 

 graphical features under a subsequent topic. 



Just across the line in Franklin county, 

 and near the village of Franklin Falls, there 

 are two separated ledges of limestone. The 

 dips are low and with the calcareous beds 

 are rusty horublendic gneisses and some 

 graphitic quartzite, the latter being certainly 

 sedimentary and the former probably the 

 same. Intrusions of anorthosite have served 

 to obscure the larger relations. 



In Essex county, to the south, in St. Ar- 

 maud township, a double bed of white, crys- 

 talline limestone outcrops at the foot of the 

 steep, westerly spur of Whiteface mountain. 

 It lies embedded in feldspathic gneisses, but 

 anorthosites outcrop further up the slope. 

 In JN'orth Elba, the next township eastward, 

 and on the western slopes of Sentinel moun- 

 tain, in the Wilmington pass, a small ledge 

 of limestone has been met, obscurely ex- 

 posed in the bed of a little brook. Passing 

 to Keene township, the next one east, there 

 are a number of exposures in the northern 

 portion that together constitute a pro- 

 nounced belt. From a point a mile south 

 of Keene Center for several miles to the 

 north, until one passes into Jay, they may 

 be located first on the west side of the valley 

 and then on the east. Quartzites in small 

 amount and a great thickness of dark, rusty 

 hornblendic gneisses accompany them. 

 Away from the central valley and well 

 up into the bounding ranges of mountains, 

 limestones have been discovered both in the 

 eastern and southeastern portions of Jay. 

 Over the high divide in Chesterfield town- 

 ship, the next one to Jay on the east, two 



exposures have been met, each time in- 

 volved with gneisses, but each time in a 

 region where huge intrusions of anorthosite 

 are likewise serious factors in the geology, al- 

 though at some distance from the limestone. 

 In Lewis township, next south, as well as 

 in Elizabethtown which lies beyond, a 

 long succession of limestones and quartzites 

 in a general north and south belt, are met 

 over a stretch of at least 15 miles, but they 

 are much broken up by anorthosites and 

 basic gabbros. In two or three instances, 

 however, the ledges are of the greatest 

 stratigraphical interest, as I shall shortly 

 bring out. 



In the valley of Lake Champlain a small 

 exposure of limestone with much associated 

 graphite forms the extreme point at the 

 picturesque Split Rock, Essex township, a 

 landmark to all travelers by steamer on the 

 lake. While the amount of limestone is 

 not great, the associated gneisses are in con- 

 siderable development, before they are re- 

 placed by anorthosites, which make up the 

 main part of the Split Rock range. No 

 more limestones are then met until a point 

 is reached in the hills in the extreme south- 

 western part of Westport, where again a 

 small ledge has been located in the midst of 

 an area consisting chiefly of the plutonic 

 intrusives. In Moriah township, both on 

 the lake near Port Henry and back in the 

 upland valley which rises to the westward 

 from the lake, the limestones are frequent 

 and of considerable thickness. Next the 

 lake they are the best exposed and thickest 

 of any outcrops in the eastern part of the 

 mountains. Details of the exposure have 

 already been printed by me. In Crown 

 Point and Ticonderoga, the next townships 

 south along the lake, small ledges have been 

 located in many places and relatively large 

 areas of the associated gneisses, and if we 

 pass right down into Washington county, on 

 the south, we shall find in the high narrow 

 ridge that lies between Lake Champlain 



