78 



SCIENCE 



[N. S. Vol. XLIX. No. 1256 



In these waters were laid down thousands 

 of feet of Cambrian and Ordovician sedi- 

 ments which later became the sandstones, 

 limestones and shales now found along the 

 shores of Lake Champlain and for a few miles 

 eastward. 



liTot long after the close of the Ordovician, 

 metamorphism occurred and the sedimentary 

 beds became mainly schist, slate and gneiss, 

 although there were also quartzite, conglom- 

 erate and eilieious limestones where the alter- 

 ation was less complete. The marbles of Rut- 

 land County are the result of a somewhat 

 varied phase of this metamorphism, acting 

 chiefly on Cliazy and Trenton beds. 



Upheaval, folding, faulting and dike intru- 

 sion came at this time, as did also the eleva- 

 tion of the present Green Mountains. The 

 sedimentary beds had been laid down before 

 the final elevation upon the eroded and sunken 

 Pre-Cambrian. 



iNow came an immense interval when, so 

 far as there is any evidence, practically no 

 rook formation occurred in Vermont. There 

 are slight exceptions. A bit of Devonian on 

 the shores of Lake Memphremagog, a trifle of 

 Silurian on the extreme southern border of 

 the state and a larger, but comparatively in- 

 significant belt of Tertiary with its most im- 

 portant outcrop, the Brandon Lignite, are all 

 before the Pleistocene. 



What happened during the incalculable time 

 between the Ordovician and the Pleistocene no 

 one knows, but there is no doubt that during 

 this age-lon£ interval erosion beyond imagin- 

 ing must have taken place, and in many re- 

 spects the land forms were changed. 



As is well known, Vermont is decidedly a 

 mountainous state. There is, to be sure, 

 abundance of level groimd and good tillable 

 land, but dominating all are the mountains. 

 In single townships there are thirty or forty 

 peaks of noteworthy size and in some instances 

 more than half of these have never been named. 

 In northern Vermont the Green Mountains 

 are somewhat irregularly scattered, but aboiit 

 fifty miles south of the Canadian border they 

 come together in the single range which con- 

 tinues southwards. By this range Vermont 



is sharply divided into the eastern Connecticut 

 Valley and the western Champlain Valley. 



Any one who journeys through the state finds 

 it easy to pass by good roads from north to 

 south, but from west to east it is often very 

 difficult and in many places impossible. Even 

 politically Vermont has an east and west side, 

 and the very shape of the state is suggested 

 by the presence of this north and south series 

 of mountains. 



Naturally, the name of the state recalls only 

 the Green Mountains and certainly the i^eaks 

 and foothills of this range are by far the most 

 imiportant physical features. On the western 

 border, however, is the not inconsiderable 

 Taconic Range and the series of Sand Rock 

 Hills, while east in the Connecticut Valley 

 are the Granite Hills. 



Probably the Taconics were formed some- 

 what later than the better known Green Moun- 

 tains. They begin just south of the middle 

 of Vermont and continue, as the Berkshire 

 Hills, into Massachusetts. Though far less 

 important than their larger and more wide- 

 spread associates, the Taconics are not insig- 

 nificant. They extend for many miles and 

 include a nvunber of summits over three thou- 

 sand feet high. Equinox in Manchester is 

 nearly four thousand feet high. In passing 

 through the beautiful valley from Bennington 

 to Rutland the Taconics are conspicuous on 

 the north and the Green Mountains on the 

 south, and the two ranges differ noticeably 

 in outline. The Taconics are largely syn- 

 clinal in structure, while the Green Mountains 

 are anticlinal or monoclinal. Says Dale in 

 " Taconic Physiography " :" 



The synclinal mountains must correspond to the 

 original valleys and the anticlinal valleys to the 

 original mountains. 



This statement also gives a hint of the 

 great extent to which erosion has taken place 

 in these mountains. This is also shown by 

 the following from the same article : 



As the limestone of the valley underlies the 

 sohist these valleys must originally have been cov- 

 ered by schist and therefore about half a mile of 



= Bulletin 279, U. S. 6. S. 



