INDEX. 165 



Page. 



Fossils : human bones not found before the historic period .- 3, 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 ., . , v |8 



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 - 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 - - 150 



LacTravers - - 150 



Lias deficient in the United States - - 55 



Limestone, primordial - . 28 



Traversed by serpentine - , .. 29 



Vertical lamina: % - , 99 



Hydraulic , - - -u . - 101 



