580 Indications of Fertility or Barrenness of Soils. 
climate, and to place us, as it were, in well-cultivated districts, 
several degrees nearer the equator, and reduce the highest of our 
cultivated hills several hundred feet. 
VI.— GEOLOGICAL SITUATION. 
The geological character of the district in which lands are 
situated is also a criterion by which to judge of fertility or bar- 
renness. From a long-continued series of observations, I have 
satisfied myself that certain geological districts, which are more 
accurately defined and more easy to identify than one would at 
first imagine, are composed, almost entirely, of fertile land, and 
others almost entirely of barren land. And it will be found on 
examination that where two differently constituted geological form- 
ations come in contact with each other, the land will be fertile 
at that point ; and in many cases it extends for a considerable 
distance on each side of the junction. If this be the case, we have 
in geology, or at least in that information which is the result of a 
study of geology, a very powerful means of assisting the judgment. 
The limits of the different great geological deposits being so 
marked, and the general character and capability of the soil of 
each being so uniform, it would appear rather a matter of surprise 
that geology, and the immense body of information that the prac- 
tical study of the science cannot fail to supply, have not hitherto 
been made use of as an important featui'e by which to judge of 
the barrenness or fertility of soils. I am aware it will require 
time and labour to obtain a sufficient knowledge of this science, 
so as to be of any use to the person attempting to apply it as a 
test ; and it will require much more labour and time to master as 
much of botany as is absolutely necessary : but this will only 
show how absurd has been the practice of calling in the assistance 
of persons who have never spent five minutes of their lives in the 
practical study of either. To show how geology may assist in the 
important business of judging of the fertility or barrenness of soils, 
it will be necessary to give a cursory description of the principal 
strata, classified and geologically arranged, as they are naturally 
exhibited in the rocks and soils of Great Britain. 
The rocks and soils of Great Britain have been classed under 
three general divisions, denominated the Tertiary System, the 
Secondary System, and the Primary System ; and those have been 
subdivided into several series of formations, each containing a 
great number of alternating deposits, which have undergone a 
further subdivision by geologists, which we will proceed to notice, 
in a summary manner, without entering into minute details. 
