C. R. Lone/well — Triassie Rocks in Connecticut. '223 



Art. XXII. — Notes on the Structure of the Triassie 

 Rocks in Southern Connecticut; by Chester E. Long- 

 well. 



I. A Group of Small Faults. 



Good exposures transverse to the strike of the rocks 

 are Tare in the Connecticut Lowland, and accordingly all 

 students of structure in this region have found it neces- 

 sary to draw generously on inference in Teaching their 

 conclusions. It is therefore especially important that 

 every available exposure should be studied and described 

 in detail. Dr. H. II. Robinson, Superintendent of the 

 Connecticut Geological and Natural History Survey, 

 recently called the writer's attention to a tunnel through 

 Saltonstall Eidge about four miles east of New Haven. 

 This tunnel, constructed in 1901 by the New Haven Water 

 Company, was described from the engineer's viewpoint 

 by Mr. Edward E. Minor, 1 but apparently its existence 

 has not been commonly known among geologists. The 

 purpose of the tunnel is to conduct water from Farm 

 River into Lake Saltonstall,- an important reservoir, at 

 times of protracted drouth. Ordinarily the north end of 

 the conduit is kept closed and the floor is covered by only 

 a few inches of water. Mr. Minor, General Manager of 

 the water company, kindly gave permission for a study of 

 the tunnel and furnished equipment for the purpose. Dr. 

 Robinson assisted in making the necessary measurements, 

 and the writer has discussed the results with him. A 

 part of the information for the following description was 

 taken from Mr. Minor's paper, referred to above. 



Description of the Tunnel Section. 



The accompanying sketch map (fig. 1) shows the loca- 

 tion of the tunnel and indicates the general geology of 

 the immediate area. The rocks are Triassie sandstones 

 and shales with three interbedded lava sheets. Through- 

 out the Connecticut Lowland these rocks have a general 

 inclination eastward, but evidently there has been con- 

 siderable warping which is responsible for local varia- 

 tions in dip and pronounced curvature of surface out- 



1 Proe. Conn. Soe. Civil Eng., 1904, pp. 12-21. 



Am. Jour. Sci. — Fifth Series, Vol. IV. No 21.— September, 1922 

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