VERMONT AND WESTERN MASSACHUSETTS. 441 



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

 statement, it may be mentioned that the Coast Ranges and the Sierra 

 Nevada of California are placed in the Azoic by Professor liogers. At 

 that time nothing had been ascertained in regard to the geological age 

 of these chains ; but they are now known to be made up of rocks not 

 older than the Carboniferous, the Coast Ranges in fact being of Creta- 

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



Professor Rogers states that the " Azoic sediments " were succeeded 

 by tliose of Palaeozoic age, " in some quarters apparently with, in some 

 without, the interruption of a disturbance of levels." The merging of 

 the Azoic with the Metamorphic Palaeozoic under one color on the map 

 was said to have been 



" made indispensable by the absolute impossibility of ascertaining at present 

 the true base of the Pala;ozoic system, for the history of Geology forbids us to 

 believe that research has yet detected the actual horizon of the dawn of ani- 

 mal and vegetable life upon our globe." 



Professor Rogers, at that time, seems to have known little or nothing 

 of what had been clone toward developuig the geological structure of 

 the country, either by the Lake Superior Survey, or by that 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 

 " semi-raetamorphic " and a " true metamorphic " system. 



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

 — from which in a northeastern direction the rocks become less and 

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

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

 assistance in unravelling the intricacies of New England geology. 



In 1849 the first published statement appears to have been made of 

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

 of the continuity through New England of the Canadian formations. 

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

 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 which we have stated seem to show that the sandstones and red 

 slates with their chromiferous chloritic bands, are identical with the dolomitic, 

 chloritic and quartzose rocks of Sutton valley, and these with the serpentines 

 and quartzose rocks of the valley of the Missisquoi ; so that the whole of the 

 Green Mountain rocks, including those containing the auriferous quartz veins, 

 belong to the Hudson River group, with the possible addition of a part of the 

 Shawangunk conglomerates. The fossiliferous rocks of the St. Francis valley 



