INDEX. 165 



Page. 



Fossils . human bones not found before the historic period - - 94 



Vegetable, predominate in the carboniferous group 112 



At Fort Snelling 135 



At the Falls of St. Anthony - 137 



G. 



Geology useful to agriculture - 8 



Definition of 13 



Gneiss, a stratified rock - 27 



Decomposed, near Georgetown, District of Columbia - 28 



Of the Himalaya chain - 37 



In Western Africa - . 37 



Anticlinal, at Georgetown - - 95 



Granite, trappean rocks ejected from beneath - . 25 



Porphyritic - - 26 



Description of - 27 



Graphic in Delaware ^ . 27 



Grauwacke restricted by Mr. Murchison to the Cambrian system - 36 



Gravel, calcareous, useful as a manure - 9 



Beds, origin of - 69 



Green sand formation in the United States - 59 



Green bay, flux and reflux of Lake Michigan - - 120 



Gypsum, deposites of, in Virginia - 116 



Harper s Ferry - - - 99 



Hornblende, porphyritic, in Delaware - - 29 



Huron, lake, incorrect maps of - - 118 



I. 



Inorganic bodies, definition of - - -13 



Intrusive rocks, nature of - - 17 



Iron, where found - 4 - - - - 70 



Uncertain extent of the deposites at Frostburg - - 106 



Aggregate thickness of the beds in Ohio and South Wales - 1 14 



K. 



Kupferschiefer, or copper slate - ... 52 



Supposed locality in the United States - 53 



L. 



Lac qui Parle - &amp;gt;**.- 150 



Lac Travers - - 150 



Lias deficient in the United States ? . 55 



Limestone, primordial - - * - 28 



Traversed by serpentine -.- . . 29 



Vertical lamina: . 99 



Hydraulic - . - ... . ^ 101 



