BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 5, pp. 213-224 February 23, 1894 



GABBROS ON THE WESTERN SHORE OF LAKE CHAHPLAIN 



BY J. F. KEMP 



{Read before the Society December 28^ 1893') 

 CONTENTS 



Page 



Introduction \. 213 



Review of the Geology of the Adirondacks 214 



Distribution of the Gabbros 215 



Facies and mineralogic Composition of the Anorthosites 215 



Occurrence and Petrography of the basic Gabbros 217 



Titaniferous Magnetite Ore Bodies 222 



Contacts of Gabljro and Limestone 223 



Conclusions 224 



Introduction. 



The present contribution deals with certain igneous rocks in the town- 

 ships of Ticonderoga, Crown Point, Moriah,\Vestport, Essex, Willsborough 

 and Chesterfield, which lie along the western shore of lake Champlain, 

 in Essex count}^, New York. In them the most important phases of the 

 great igneous body that forms the bulk of the Adirondacks are illus- 

 trated, and in many particulars petrographic details are adduced which 

 have not been previously noted from this region. The field work in 

 Moriah and Westport was done with the support and under the direc- 

 tion of Dr F. J. H. Merrill, director of the New York State Museum, and 

 in the other towns, except Chesterfield, with the aid of the trustees of 

 Columbia College, while in Chesterfield and a number of interior town- 

 ships not mentioned here the writer has had the support and direction 

 of Professor James Hall, state geologist. These results are published 

 with the approval of all concerned.* For five or six years past the 

 writer has been making annual trips into the Adirondacks by way of 

 reconnaissance, and the conclusions are checked, therefore, by a wider 



* Geologic maps and section? of these and the rennaining townships of the mountains have been 

 or are to be drawn and descriptions written. Those on Moriah and Westport will be submitted to 

 Dr F. J. H. Merrill, those on the others, so far as completed, to Professor .James Hall. To each of 

 these gentlemen for permission to use the materials employed in this paper the writer expresses 

 his grateful acknowledgments. 



XXIX— Bull. Geol. Soc. Am., Vol. 5, 1893. (213) 



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