BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 5, pp. 515-530 April 25, 1894 



EASTERN BOUNDARY OF THE CONNECTICUT TRIASSIC* 



BY W. M. DAVIS AND L. S. GRISWOLD 



{Read before the Society December 28, 1893) 1 



COXTENTS 



Page 



Previous Studies 515 



Geological History of the Region 516 



Faults 518 



Faults in General 518 



Elements of a Fault 520 



Deformation along the eastern Boundary of Connecticut Triassic 521 



General Account of the eastern Boundary 521 



Evidences of Faulting along the Boundary 521 



Absence of direct Evidence 521 



Discontinuity of Triassic Strata 522 



Fault-line Valley 523 



Associated Dislocations 523 



Alteration of Crystallines along the Border 524 



Association of marginal and internal Faults 525 



Additional Evidence from the separate Faults 525 



Another Explanation of the Contact Line considered 528 



Measurement of the Faults 528 



. Final Considerations 530 



Previous Studies. 



The i)rcvious studies of the Triassic formation of Connecticut, carried 

 on by the senior author of this paper, with the aid of several assistants 

 during various summer vacations for the United States Geological Sur- 

 vey, as well as independently during successive sessions of the Harvard 

 summer school of geology, have been reported upon at different times, 

 as mentioned in a list of papers in a previous number of this Bulletin.t 

 Since then a popular essay, '' The Lost Volcanoes of Connecticut," has 

 been published in the Popular Science Monthly for December, 1891, by 

 the senior author. 



All these previous studies have been chiefly concerned with the struc- 



* Puljlished by permission of the Director of the United States Geological Survey, 

 t Bull. Geol. Soe. Am., vol. 2, 1891. p. 41G. 



LXXII-Bui.r,. GEon. See. Am., Vol. 5, 1893. (515) 



