518 PROCEEDINGS OE THE WASHINGTON MEETING 



The second paper presented was 



BASAL CONGLOMERATE IN LEHIGH AND NORTHAMPTON COUNTIES, PENNSYL- 

 VANIA 



BY FREDERICK B. PECK 



Contents 



Page 



Scope and purpose of the paper 51s 



Application of the term "basal conglomerate" 518 



Previous descriptions of the beds elsewhere 518 



General description 518 



More detailed description of special localities 519 



Summary 521 



Scope and Purpose of the Paper 



In the present paper no attempt is made to cover the entire area represented by 

 Lehigh and Northampton counties even, or to treat the subject at all exhaustively, 

 but rather to describe briefl}^ certain phases of this basal series as it occurs near 

 Easton, on the Delaware river, in Northampton county, and at a few other local- 

 ities southwest of Easton, in Lehigh, including one locality just over the line in 

 Berks county. 



Application of the Term "Basal Conglomerate" 



The term " basal conglomerate" as here used refers to that lowest member or 

 series of beds belonging to the Cambrian which lies unconformably on the pre- 

 Cambrian gneisses, but is conformable with the overlying lower Cambrian dolo- 

 mites. It presents a variety of phases, at times assuming the character of a rather 

 coarse conglomerate, an arkose, a dense fine grained bluish or grayish quartzite, an 

 impure argillaceous quartzite, or a dense ferruginous, somewhat jaspery, quartzite. 



Previous Descriptions of the Beds Elsewhere 



This series has already been fully desciibed by Mr Walcott^ as it occurs farther 

 to the southwest in York county. It has also been described by Wolf and Brooks f 

 in Essex county, New Jersey, as the " Hardistonville quartzite," and by Kummel 

 and Wellerj from the same locality as the " Hardiston quartzite," the latter gen- 

 tleman preferring the shorter and more convenient local name of the township in 

 which, rather than of the town near which, typical outcrops occur. 



General Description 



The band of pre-Cambrian rocks which extends across the northern portion of 

 New Jersey as a series of parallel ridges, with intervening valleys of Cambrian 

 dolomites and dolomitic limestones, crosses the eastern border of the state of Penn- 



*Bull. U. S. Geol. Survey, no. 134, 1^97. 



fU. S. Geol. Survey, Eighteenth .Annual Report of the Director, part ii, p. 442 et seq. 



I Bull. Geol. Soc. Am., vol. 12, p. 14!» et seq. 



