gULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 VOL. 15, PP. 461-482, PLS. 42-44 OCTOBER 25, 1904 



NEW STUDIES IN THE AMMONOOSUC DISTRICT OF NEW 



HAMPSHIRE 



BY C. H. HITCHCOCK 



(Presented before the Society December 30, 1903) 

 CONTENTS 



Page 



Introduction < 461 



Fossils 462 



Age and occurrence 462 



Specimens from black slate 462 



Specimens from limestone 462 



Specimens from lake Memphremagog 463 



The typical fossiliferous area 463 



Igneous ejections 465 



Hornblende rocks 467 



Contact phenomena — Lyman schist. 467 



Distribution of the limestones 469 



The conglomerates 471 



Other conglomerates , 472 



Areas of argillite 474 



Lisbon-Swiftwater complex 476 



Description of the map 479 



Conclusions 479 



Description of Dalmanites lunatus ; by Avery E. Lambert 480 



Explanation of plate 44 482 



Introduction 



In 1877 the writer published in the second volume of the Geology of 

 New Hampshire a general description of the rocks of the Ammonoosuc 

 district, the region extending from Woodsville to Lancaster, where the 

 Connecticut river bends conspicuously to the west and has apparently 

 annexed a part of Vermont to New Hampshire. The Connecticut has 

 cut across a mountainous range in what is known as the Fifteen Miles 

 falls, causing the drainage of the upper part of the state to unite with 

 that of the Passumpsic river. On some other occasion I hope to revive 

 an old theory, advocating the former drainage of the upper Connecticut 



LIX— Bull. G-eol. Soc. Am., Vol. 15, 1903 (461) 



