FOSSILS OF THE ANTERIOR AND POSTERIOR SHALES: 

 BY S. WARD LOPER. 



The Area examined. 



In accordance with iustructioDs received from Professor Davis last June, I 

 have endeavored to test the continuity of the anterior and posterior fossiliferous 

 shales associated with the trap ranges of the Triassic formation of the lower 

 Connecticut valley. I have examined carefully the shale outcrops lying 

 between the anterior and main trap ridges for nearly the whole distance 

 across the state (about 50 miles), and have also looked for the posterior 

 shales over a considerable part of this distance. 



Although the work assigned me is not fully completed, I am able to re- 

 port much that is of a satisfactory nature. Openings have been made along 

 both the anterior and the posterior shales in several of the faulted blocks of 

 the formation, and the beds thus disclosed, as well as the fossils obtained 

 from them, show an indisputable correspondence in the stratigraphy. 



About 450 specimens have been collected, exclusive of many hundred 

 fossils which have been taken during the past twenty years from the shale 

 beds of Durham and vicinity. About twenty-four species of fishes and 

 plants, some hitherto undescribed, are now known from these localities. A 

 comparison of the species from the different localities of the anterior and the 

 posterior shales shows a correspondence in the fauna and flora, clearly sus- 

 taining the theory of the original continuity of the horizons through all the 

 now faulted blocks of the Triassic formation. 



Along the middle and southern ranges there has not been much difficulty 

 in finding available points for making openings : but toward the northern 

 line of the state, above the gap of the Farmington river at Tarriffville, the 

 shales have been generally inaccessible on account of the great amount of 

 drift by which they are buried. The red sandy beds and the blue shales 

 associated with the black shales, are, however, traceable entirely across the 

 state ; and with sufficient time for closer search at certain points, there is little 

 reason to doubt that the fossiliferous shales might be uncovered in the 

 northern area. 



The method of searching for the shales has been to walk over all the strip 

 of country between the anterior and main trap ridges, and also, so far as 

 has been possible in a single season, between the main and posterior ridges, 

 making a thorough examination for outcrops of the fossiliferous beds in 

 their appropriate positions. Several new localities yielding many valuable 



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