APPENDIX VI. 



Extract from Prof. Thompson s Address, on the 

 Natural History of Vermont. 



The Green Mountains have, for some years past, presented to 

 geologists an interesting problem, which was the determination 

 of their geological ogc and character, and particularly the age and 

 character of that portion of the western slope of these mountains 

 which have been denominated the Taconic System. And as the 

 larger part of this range of mountains was within the limits of 

 Vermont, the attention of the geologists of the country was direct- 

 ted to the geological survey of that State, as being likely to fur 

 nish a satisfactory solution of the problem- and during the con 

 tinuance of the survey, that object was kept constantly in view by 

 those engaged in it. Many sections were traced from the well 

 known Silurian rocks, which occupy the valley of Lake Champlain, 

 to the center of the Green Mountain range, and many facts were 

 brought to light which have an important bearing upon the prob 

 lem which I have mentioned ; but just as the examinations w r ere 

 being completed, and the results and facts were to be brought to 

 gether, systematized and weighed, the survey was suspended ; and 

 whether it will ever be resumed or not, is a problem which time 

 only can solve. 



The rocks in the western part of Yermont, in the valley of 

 Lake Champlain, arc highly fossiliferous and clearly belong to 

 that portion of the lower Silurian, denominated by the New York 

 geologists, the Champlain group. To the eastward of these, and 

 mostly in the south part of the State, lie the so-called Taconic 

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