530 Natural History of the N.E. Extremity 



features of this region, which has hitherto been undescribed 

 and unvisited for scientific objects. 



The highest beds alone in this elevated country consist of 

 secondary sandstones, and shales, containing beds of coal and 

 iron ; the whole series, being comprised within a thickness of 

 from 100 ft. to 450 ft., approaching to horizon tality. Beneath 

 them are beds of grits, like the millstone grit, coarse conglo- 

 merates, and carboniferous sandstones, upwards of 300 ft. thick. 

 These repose upon the old red sandstone group, whose beds 

 are inclined, and are no less than 6000 ft. thick, comprising 

 an immense series of laminated greenish-brown sandstones, 

 red sandstones, and shales, with innumerable Producta and 

 Encrinltes; blue and greenish shales and argillaceous sand- 

 stones, containing some interstratified beds of conglomerate 

 limestone; a few thin subordinate seams of sub-crystalline 

 shelly limestone or marble ; some occasional deposits of 

 vegetable remains, partially carbonised; and traces of car- 

 bonate of copper, and numerous remains of obscure Fuco- 

 ides. These form the mass of the Alleghany group here. 

 Below them are innumerable coloured shales; red, blue, green 

 and dark grauwacke slates, and argillaceous beds ; altogether 

 occupying a thickness of 2300 ft. To these succeeds the first 

 series of transition limestones, with few fossils, 6000 ft. thick. 

 A second parallel of grauwacke rocks and slates succeeds, 

 characterised by encrinital casts, Producta, and occasionally 

 by trilobites and Fucbides, comprising a thickness of 3000 ft. 

 more, and followed by the second limestone parallel, and an 

 enormous series of other grauwacke and transition rocks, 

 which it is not my purpose further to advert to here. These 

 are the mean results obtained from two sections, which traverse 

 a hundred and twenty miles of this country. 



A third section, eighty miles to the southward of the fore- 

 going, exhibits the series as follows : — 



! Feet. 



The carboniferous secondary series ~ - 1000 



The old red sandstone group ----- 1800 

 Red and dark shales beneath, to the base of the Alleghany 



Mountains ______ 1700 



Grauwacke shales, with some small calcareous beds - - 3800 

 Grauwacke siliceous grits, conglomerates, and beds containing 



Fucoides - - - - - - 3500 



Transition limestone, sometimes highly siliceous, with few 



fossils - - - - 6000 



Second series of ferruginous sandstones and conglomerates - 3500 

 Followed by other limestones, and again by sandstones, many 



thousand feet thick. 



A fourth section, thirty miles to the south, shows the series 

 with some variations. 



