RECONNOISSANCE OF THE LYON NITRATE PROSPECT. 



whole eastern slope of the eastward dipping monocline that forms 

 the Guadalupe Mountains. Even the sandstones of tliis series are 

 prevailingly calcareous and the series is provisionally called Creta- 



FIG. 1. View of end of point upon which nitrate outcrops occur, showing typical series of strata. 



ceous, though this correlation is only tentative. No fossils were 

 found. There are a few meager exposures of a red, indurated argillite, 

 but its relation to the rest of the series was not determined. All 



strata dip gently toward 

 the east with occasion- 

 ally a small amount of 

 local folding or faulting. 

 The slope is dissected by 

 many steep-walled can- 

 yons, in which perhaps 

 300 feet of the Cretace- 

 ous (?) series are ex- 

 posed. The general 

 character of the series is 

 shown in figure 1 . 



The nitrate prospect 

 is located at the bottom 

 of the wall of Dark Can- 

 yon, on both sides of a 



FIG. 2. Sketch of Dark Canyon, showing location of nitrate small point formed by Jl 

 deposits. , ,, 



bend of the canyon, as 



is indicated by the rough sketch map, figure 2. At this point the 

 canyon is perhaps 200 feet deep, and is set in rocks which do not 

 seem to differ in any way from those of the mountain slope in 



