94 



Lesley.] ^* Tt [April 3, 



Mr. Benjamin Smith Lyman, Assistant on the Geological Survey of the 

 State, whose Report on the Trias Brown Sandstone Belt of Bucks, Mont- 

 gomery and Chester counties, Pa., is not yet quite ready for publication, 

 informs me that the place assigned to coal in the above well record would 

 come about 11,000' below the top, or 10,000' above the bottom of his gen- 

 eral section of the formation ; the coal -bearing shales of Phcenixville be- 

 ing say 3500' or 4000' above the conglomerate base. 



His long and exhaustive survey ot the district has resulted in giving a 

 combined thickness of more than 21,000 feet to these Mesozoic strata ; in 

 a demonstration of the duplication of its measures along the Delaware 

 river ; and in the discovery of both longitudinal and transverse anticlinal 

 aud synclinal flexures of considerable size. The latter system of folds is a 

 very remarkable phenomenon, seeing that the folds lie with their north- 

 ern ends abutting against (or riding over) the Durham hills, that range of 

 Azoic highlands which extends from Reading into Northern New Jersey. 



Mr. B. S. Lyman said : 



Although the precise position of the Revere, or Rufe's Corner, well- 

 boring has not been indicated within several hundred feet, it appears that 

 the so-called coal bed is part of a 600 or 800 feet thick series of generally 

 hard green and dark-red shales at something like 11,000 feet below the 

 top of the Mesozoic rocks, mainly red shales, of Bucks and Montgomery 

 counties, and 10,000 feet above the bottom of them, and 6000 feet above 

 the hard blackish shales of the Phcenixville tunnel. 



With a sketch he showed the course of the outcrop, a mile or so in 

 width, of the green and dark-red shales, including the so-called coal bed 

 and one or two other blackish shale layers, with generally a gentle north- 

 westerly dip, from the Delaware river near Mil ford, N. J., along the east, 

 south and west sides of a basin to Rufe's Corner ; thence northwestward, 

 westward and southeastward, round Stony Point and Bucksville, in sad- 

 dle form, east of the Haycock mountain, nearly to Ottsville ; then in 

 almost a straight line southwestward for a dozen miles, past Perkasie and 

 Sellersville ; and five or six miles further southwest, though bending 

 slightly northward at Tylersport upon the southeastern disappearing end 

 of a rock saddle ; but near Sumneytown bending sharply round a more im- 

 portant saddle so as to reach Harleysville, half a dozen miles to the south- 

 east ; and there with a like decided bend in the opposite direction, but 

 with a wider sweep, turning southwest and then nearly west, passing a 

 little more than a mile south of Shwenksville, and so in a straight course 

 to the Schuylkill, between Linfield and Sanatoga and some three miles 

 below Pottstown. 



The course of these comparatively hard beds is marked nearly every- 

 where by a decided ridge, particularly well defined between Ottsville and 

 Sumneytown, and tunneled through at Perkasie. As the beds are partly 

 green, their course is also indicated by the yellowish or greenish gray 



