BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 VOL. 16, PP. 419-446, PLS. 71-81 OCTOBER 25. 1905 



PETROGRAPHY OF THE AMPHIBOLITE, SERPENTINE, AND 



ASSOCIATED ASBESTOS DEPOSITS OF BELVIDERE 



MOUNTAIN, VERMONT * 



BY VERNON FREEMAN MARSTERS 



(Presented before the Society December 30, 1904) 

 CONTENTS 



Page 



Early views on the stratigraphy of Vermont 420 



Location of Belvidere and Lowell areas 420 



Economic importance of serpentine 422 



Topography of Belvidere region 422 



Rock types 424 



General distribution 424 



Schists 424 



Brief discussion of composition 424 



Age of the schists 425 



Amphibolites. . . 426 



A real distribution 426 



Macroscopic characters and mineral composition 426 



Serpentine 427 



Macroscopic characters and mineralogy 427 



Local talc lenses 428 



Structure of the region 428 



Early knowledge of asbestos and its uses 430 



Development of Canadian industry (Thetford) 431 



Geology of Canadian area 432 



Vermont asbestos 432 



Occurrence . . 432 



Kinds — slip-fiber and cross fiber 433 



Structure of cross-fiber veins 435 



Discussion of probable modes of growth 435 



Amphibolite 436 



Micro-structure and mineralogy 436 



* In the field work on which this paper is based I beg to acknowledge the hearty cooperation 

 of Professor G. H. Perkins, state geologist of Vermont, as well as the assistance of Judge M.E. 

 Tucker, whose detailed and accurate knowledge of the area, gained during his search for asbestos 

 rock, was cheerfully placed at my service. To Mr B B. Blake, of Eden corners, and Mr Silsbey, 

 of Lowell, I wish to expre.-s my thanks for assistance freely given hi that portion of the area with 

 which thf-y are fully acquainted. 



In the investigation of the petrographic problems involved I beg to acknowledge the invaluable 

 assistance and many suggestions offered by Professor J. F. Kemp, Dr C. P. Berkey, and Dr A. A. 

 Julien, of Columbia University. 



LVII— Bull. Geol. Soc. Am., Vol. 16, 1904 (419) 



