INDEX. 165 



Page. 



Fossils ; human bones not found before the historic period - - 91 



Vegetable, predominate in the carboniferous group - 112 



At Fort Snelling- - - - - - - 135 



At the Falls of St. Anthony - . , . - 137 

 G. 



Geology useful to ag-riculture ...... 8 



Definition of - - - - - - 13 



Gneiss, a stratifi.ed 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 . = . . . nf. 

 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 - 114 

 K. 



Kupferschiefer, or copper slate ------ 52 



Supposed locality in the United States - - - 53 

 L. 



Lac qui Parle - - - - - - - - 1 50 



Lac Travers ........ 150 



Lias deficient in the United States ----- 55 



Limestone, primordial ------- 28 



Traversed by serpentine - - - . - 29 



Vertical laminae ----- . 99 



Hydraulic - ^ - - . , - 101 



