Vieivs of Whitney. 
229 
his report the subject is fully discussed, and a resume of his 
conclusions is given as follows:* 
1st. Each mining district in the lead region has its metallifer¬ 
ous deposits confined to a certain vertical range, which does 
not in any one locality or group of diggings extend through 
the whole series of lead-bearing strata. 
2d. The mineral deposits do not extend into the upper, sand¬ 
stone, and the cracks or joints in that rock are not continu¬ 
ous with or dependent on those in the groups above or below. 
3d. The Lower Magnesian Limestone has nowhere been proved 
to be a rock which can be mined in profitably for lead for 
any length of time. 
It should be noted that Whitney did not discuss the cause of 
the linear distribution of the mineral-bearing crevices; their 
origin and relation to the lines of uplift which had so greatly 
impressed Percival, nor did he find any faults in the strata, 
which Percival had so specifically noted and described, Whit¬ 
ney’s statements relative to these subjects being: ‘‘There is 
no evidence in the lead region of the deposits of ore or the 
crevices being situated over or near faults or dislocations of 
the surface, or of being in any way connected with subterra¬ 
nean or deep-seated movements of the crust of the earth, such 
as would allow of the metalliferous solutions having access from 
below.” (Page 393. ) This is remarkable, inasmuch as disloca¬ 
tions do exist as Percival stated, and that they do certainly 
appear to have some relation to the mineral deposits, a relation 
which needs investigation. 
Professor Whitney’s report is well illustrated by drawings of 
the various forms of crevices, openings, chambers and deposits 
of ore. Many of these illustrations, with a memoir upon the 
Lead Deposits of the Mississippi Valley, were published in the 
Mining Magazine.! 
Professor Whitney did not fail to note and to fully discuss 
the phenomenon of the absence of drift deposits within the 
limits of the productive lead region, and gives a diagram or 
small map upon which the boundaries of the region destitute of 
drift are shown.f The conclusions to which a study of this 
* Vol. I, Hall & Whitney’s Report, p. 416. 
X Mining Magazine and Journal of Geology. 
I Report 1862, Fig. 2, pp. 118-119. 
