242 S. W. Johnson on the Soil-analyses of the 
known, the soil loses in mineral matter what the crop gains, it is 
‘doubtful if in any given case chemical analysis can indicate this 
difference with certainty, for the reasons that the accidents which 
affect analysis make the limits of inaccuracy, to cover more than 
the loss by years of cropping. When we take into account the 
changes that are constantly progressing in the soil when under 
cultivation—changes by which the disintegration is hastened, 
changes by which it is made in many instances more retentive 
of soluble matters—when we remember that most cultivated 
crops, although they carry off in seed, stem and foliage a quan- 
tity of mineral matters, yet derive these in part from a depth 
that has 10 per cent (eight-seventy-ninths) of exceptions, the 
existence of which like that of the rule itself, is only to be 
established by comparison with the plain agricultural fact. 
In short, if we admit the result aia. Owen and Peter would 
have it—of what use or interest is it : 
The 8d point, is that analysis shows “the peculiarities of the 
soils derived from different geological formations.” Says Dr. 
Owen, “these analyses most distinctly show that certain geolog- 
ical formations impart to the soil more of the important mine 
ral fertilizers than others.” The reader will be able “to 8° 
that it is those formations which are composed of easily disin- 
tegrating materials, which, all other things being equal, yield t 
i tash ; 
entirely sufficient proof, we do not see the value of the “law” 
fertile soils derived from the highly fossiliferous, argillo-calea- 
reous beds of the lower Silurian, the Cretaceous and the Tertiary 
systems of the West; through the silico-caleareous soils of the 
upper Silurian, Devonian and Sub-Carboniferous limestone strata, a 
in which fossils are either more sparingly distributed or, im some 
