LETTERS TO A. GEIKIE 



places almost fade out, the limestones being gray and 

 feebly crystalline. As a consequence, also, the region 

 affords an excellent chance for studying the successive 

 stages of crystallization and other concomitant changes 

 in the metamorphosed sedimentary rocks which are associ- 

 ated with the limestone. These changes are well shown 

 along the Green Mountain and Taconic region from north 

 to south; but are exhibited more strikingly on lines from 

 east to west because these transverse lines are short 

 compared with the longitudinal. 



' In thus speaking of the Green Mountain region (the 

 Taconic included) as made of the limestone ranges and 

 the conformably associated rocks, I do not mean to im- 

 ply that this is so without exception, for Archaean rocks 

 cover nearly all of Putnam County in Eastern New York, 

 and outcrop also in Western Connecticut, and probably 

 also in Western Massachusetts, and in portions of the 

 mountain region of Vermont, as held by Prof. C. H. 

 Hitchcock. But these are small areas compared with the 

 rest. Although so small they are of the highest interest 

 in this connection, since they offer us an explanation as 

 to the origin of those sediments which were made into 

 strata of the Green Mountain region. 



14 I wish you could have given the region some study 

 when you were in New England last summer. I would 

 strongly recommend a brief visit at least to it when you 

 are again this side of the ocean. I should esteem it a 

 privilege to give you all the help I could in the study of 

 the region ; and I would say the same to any member of 

 the Geological Society. 



'In order that the precise position of the region re- 

 ferred to in my paper may be understood, and the general 

 geographical relations of its several parts and localities, I 

 send by post, at the same time with my book and letter, 

 a map of New England (part of Maine excluded) and 

 Eastern New York, for the library of the Geological 

 Society. It is one of our Government Post Route maps, 

 and I have selected it because the scale is large, and it is 

 unobscured by bad typography. The map will be also of 

 service to any members that may be interested in an 

 article I am now publishing in the American Journal 

 of Science on the Quaternary Flood of the Connecticut 

 River Valley." 



337 



