278 The American Geologist. November, isas 
1. Subterranean — eruption in dykes or accompanying basal- 
tic flows. [2.] 
2. Superficial action. 
a. Violent abrasion and transport. [13.] 
1. Concentration of iron sands. [14.] 
h. Ordinary erosion. 
2. Oceanic sedimentation. [8.] 
B. Chemical. 
a. Changes in situ. 
1. Change in the kind or quantity of iron already present in 
the rocks. 
a. Alteration of diffused ferric oxide into ferrous carbon- 
ate. [10.] 
h. Metamorphism of bog ore. [11.] 
c. Metamorphism of lake ore. [12.] 
(1. Alteration of ferrous carbonate or sulphide into ferric 
oxide. [8 in part.] 
2. Change in the kind or quantity of other minerals. 
a. Substitution of iron oxide for some non-ferriferous 
mineral. [17.] 
h. Concentration, by removal of the other constituents. 
[4.] Similar to B a 1. 
r. Electro-telluric action. [16.] 
b. Removal by chemical action and subsequent deposition. 
1. By action of heat — sublimation. [H.] 
2. By action of water. 
1. Oceanic precipitation. [Sinp't.] 
a. Secondary product of the 
H. In drainage basins. ^ decomposition of basic 
rocks. [18.] 
b. Secondary product from 
the decomposition of py- 
[ rite. [7.] 
, y ,, . (l. Saturation of porous strata. [5.] 
(2. Infiltration into cavities. [6, 15.] 
('. Deposit by springs. [9.] 
'^■\ 
Mr. W.J. McGee, in "The Pleistocene History of Northeastern 
Iowa, " revives the use of the term g*'<^st, applied by DeLuc in 
1816, and afterward by f^aton and Beck, in America, to "the 
immediate products of rock decay in situ." P. 279, EUrcuth 
Annual Report of the Director C S. Geol. Siirrci/. 
