336 A. Wing's Discoveries in Vermont Geology. 



" great central slate belt," that limestone, according to Mr. Wing, 

 not extending to the pond in Pittsford. Besides these, the long 

 Tertiary area, following the eastern border of the main mass of 

 Eolian limestone has been omitted, since it was based on a few 

 local limonite deposits, which were mainly a result of the altera- 

 tion of either the limestone, or of the slates adjoining associated 

 with the quartzyte, or perhaps partly of the quartzyte itself where 

 Impure, and which were forming during earlier as well as later time. 



On the map all the areas that are horizontally lined are lime- 

 stone areas; those vertically lined are slates (hydromica or argil- 

 laceous) ; the dotted area on the east is quartzyte, and the finely 

 dotted on the west and north, Red Sand-rock. The areas most 

 openly lined horizontally are those of the " Eolian limestone," the 

 crystalline or metamorphic limestone, which includes nearly all 

 the marbles of Vermont south of Monkton. 



The main or eastern band of the Eolian limestone follows the 

 course of Otter Creek valley, and, no doubt, determined the posi- 

 tion of the valley. There is also, north of West Haven, a west- 

 ern band, more or less complete, lying to the west of the " central 

 belt of slate." This great slate-belt extends from Weybridge on 

 the north to the southwestern corner of the State, widening south- 

 ward and spreading into the State of New York. The part south 

 of Brandon has been called the Taconic range of mountains, it 

 being properly a continuation of the Taconic range of Massachu- 

 setts. This belt of slate, over its interior, consists mostly of clay- 

 slate or argillyte (good roofing-slate in many places) (A) ; but, 

 B) there is a broad band of hydromica slate, 

 south of Whiting village, this belt is interrupted for a fourth of a 

 mile or so, according to Mr. Wing, and here the limestone to the 

 west of it connects with that to the east in Otter Creek valley. 

 The geological formations on the western border of Vermont, 

 including the Hudson River and Utica shales, with some lime- 

 stone in the former, the Trenton, Black River, Birdseye and 

 Chazy limestones, are mostly unaltered fossiliferous rocks, ana 

 hence their age was long since ascertained. The limestone areas 

 within that of the Hudson River slate are set down as Hudson 

 Mivi-r limestone in the Vermont map; but Mr. Wing's notes im- 

 ply that he thought them in part at least Trenton, yet without 

 any special discussion of the subject. 



To the east of the eastern quartzyte range there is, east of Bns- 

 Vermont map calls " talcose con^ 



, an area of "talcose schist," tn<_ *« 



belonging with the quartzyte, and the latter a hydromica slate, 



evidence in the Vermont Report. Farther t-ast._ 



ranging from the southern boundary of the State, and much of 



adjoining the quartzyte on the east side, there is on the 



ad area of gneiss, often called Green Mountain gneiss. 



rmt it is not all gneiss; for the Vermont Report states that 



Mount Mansfield, the highest mountain of the Green 



range, consist- pur\ ,.i I,]. Hti. liydr..inii i -late, md this I have 





