VERMO.NT AND \VE-<TEUN MASSACHUSETTS. 



441 



a purely imaginative one. As an illustration of the correctness of this 

 statement, it may be mentioned that the Coast llauges and tlie Sierra 

 Nevada of California are placed hi the Azoic hy Professor J{ogers. At 

 that time nothing had been ascertained in regard to the u'eolouieal ai»'G 

 of these cliains ; bnt they arc now known to ho made up of rocks not 

 older tliau the Carboniferous, tlic Coast lianges in fact being of Creta- 

 ceous and Tertiary age, with associated eruptive and intrusive matter. 



IVofessor Eogcrs states that the "Azoic sediments" were succeeded 

 by tliose of PaljJ^ozoic age, " in some quarters apparently with, in some 

 withont, tlje interruption of a disturbance of levels." The merging of 

 the Azoic with the Aletamorphic Puhcozoic under one color on the map 

 was said to have been 



''made iiulispensable by the absolute impossibility of ascertaining at present 

 the true base of the Pahto/oic system, for the hisloiy of Ceohigy forbids us to 

 lielieve lha,t rescardi has yet detected the actual horizon of the dawn of ani- 

 mal and vegetabh; Ufe upiui our globe." 



Professor P^ogers, at that time, seems to have known little or nothing 

 of what had been done toward developing the geological structure of 

 the country, either by the Lake Superior Survey, or by tluit of Canada. 

 Neither was there any other than a purely theoretical basis for his 

 division of the rocks below the Lower Silurian or Cambrian into a 

 "scmi-metamor[)hic" and a "true metamorphic" system. 



The work of the Canada Geological Survey on the borders of Vermont 

 from wluch in a northeastern direction the rocks become less and 

 less dilhcult to decipher, because their relations are less obscured by 

 metamorphism— -couKl not fail, if it were well done, to be of great 

 assistance in unravelling llie intricacies of New England geology. 



In 1819 the first published statement appears to have been made of 

 the results obtained by that Survey, bearing especially on the question 

 of tlie continuity through New Englaud of the Canadian fonnations. 

 This statement was made by Dr. Hunt, "of the Geological Conuuission 

 of Canada," and was said to be "a brief sketch of the results obtained 

 by .Mr. Logan and his associates." It reads as follows : — 



" The facts >vhich we have stated seem to show that the sandstones and red 

 skites with their chroniiferoLis chloritic bands, are identical with the dolomitic, 

 chhiritic and (piartzose rocks of Sutton valley, and these with the serpentines 

 and (piartzose rocks of the valley of the Missiscjuoi ; so that the Avliole of the 

 Green ^Mountain rocks, including those containing the auriferous quartz veius, 

 belong to the Hudson Kivcr grouj), with the possible addition of a })arl of the 



Sliawangurdv conglouierates. The fossiliferous rocks of the St. Francis valley 



