368 DARTON — GREEN POND, N. J., TO SKUNNEMUNK MT., N. Y. 



The rocks are comprised in about nine formations, of which the dis- 

 tribution and structural relations are shown in plate 17. The upper- 

 most member is a coarse conglomerate which constitutes the higher 



portions of Skunnemunk and 

 Bell vale mountains in New York 

 and of Bearfort mountain in New 

 Jersey. Its age is Middle De- 

 vonian. It is underlain b}^ a 

 series of flaggy sandstone which 

 merges into dark shales below. 

 There is another prominent con- 

 glomerate in Green Pond, Bowl- 

 ing Green, Kanouse and Cop- 



peras mountains in New Jersey, 

 and some smaller ridges in New 

 York, which is somewhat simi- 

 lar in character to the upper, 

 conglomerate, but its age is Upper 

 Silurian. There are also thin dis- 

 continuous sheets of conglomer- 

 ate or conglomerate-quartzite of 

 Oriskany age and a few small 

 areas of conglomerate, associated 

 with the Cambrian limestone. This Cambrian limestone occurs at inter- 

 vals along the margin of the belt, and is unconformably overlapped by 

 the various other members. The Helderberg limestone areas are in 

 greater part associated with the Oriskany beds, and they have been 

 found at manv localities. 



nuuKK I.— Geologic Map of northern New Jersey and 

 adjacent Portions of New York. 



The area enclosed by the broken line is shown 

 on plate 17. 



The Formations. 



Review of tJieir Investigation. — The formations have been assigned to 

 various horizons by previous observers and much uncertainty has always 

 prevailed in regard to their ages. A list of the principal observers and 

 their views is presented in the accompanying table, page 369. 



E. Emmons* and T. Sterry Huntf have expressed an opinion that 

 the conglomerates and flags were representatives of the first graywacke 

 of Eaton, but they do not appear to have made field studies of the region. 



The principal contributions have been the reports by Horton and 

 Mather ; Cook, 1868 ; Smock, and Merrill, and the announcement by 



* Geology of New York, Second District, Albany, 1842. 



fThe Taeonic Question in Geologj'-, part i: Trans. Roy. Soe. of Canada, vol. i, section iv, 1883, pp. 

 220, 253-254. 



