Nov. 11, 1869] 
NATURE 
47 
While the population was comparatively small, the 
amount of land under cultivation was also limited, only 
the better class of soils in the most fertile districts being 
chosen for corn, and the remainder used for pasturage or 
common-land ; whilst large tracts of country, capable of 
producing abundant crops, were left wild, or still covered 
with woods : but as people congregated in centres of trade, 
the demand for corn arose and increased. Although, 
however, the farmer was thus encouraged to attempt the 
tillage of waste lands hitherto neglected, little improvement 
is noticeable in the method of farming until the beginning 
of the present century; for agriculture, like all venerable 
arts, has been—until very lately—strictly conservative ; 
so much so, indeed, that many of its practices and precepts 
have come down to us but little altered since the days 
when Virgil wrote the Georgics. 
But this century, so pregnant with change to all our 
industries, has not permitted agriculture to escape 
innovation ; and notable among the signs of the time was 
the establishment, in 1838, of the Royal Agricultural 
Society, under whose auspices much has been done towards 
the removal of long-cherished and old-established pre- 
judices, and the acceptance and adoption of numberless 
improvements. 
The chemist has been, and indeed is still, hard at work 
for the agriculturist, analysing the soils on his farm, and 
advising him what artificial remedies to apply to improve 
their fertility, or to fit them for special crops. He has 
told him the reason why a rotation of crops is bene- 
ficial; because a green-crop, a root-crop, and a grain- 
crop each take different ingredients from the soil ; and 
thus, by a knowledge of their requirements, he may apply 
to each that special ingredient—if not already in the 
land—at the period when it is required by the plant, 
Nor has Geology neglected to tender her aid to agri- 
culture, by pointing out that there exists a direct relation 
between the soil of a given area and the subsoil upon 
which it rests; and that thus, by a knowledge of the 
geological features of a country, the farmer, in the 
selection of land, may not only be guided to the most 
permanently productive soil, but also to that which rests 
upon a subsoil calculated to enhance rather than depre- 
ciate its value. 
Anyone who will take the trouble to examine a geologi- 
cally coloured map of the British Isles, will see at a glance 
the general distribution, at (or zear) the surface, of all the 
various geologicalformations, from the Pliocene and Eocene 
in the east and south-east, to the Granites and Trap-rocks 
of the west and north, with the relative superficial extent of 
each. But let us take a nearer view. In Britain, as in almost 
every country in the world, and in all latitudes, superficial 
accumulations of clay, sand, and gravel occur, sometimes 
forming a mere coating of the rocks beneath, but often 
of very considerable thickness, and covering large areas. 
The earlier geologists classed the whole of these de- 
posits under the general name of Dz/wvium, and attributed 
their irregular occurrence and wide distribution to the 
effects of one great and universal deluge. They have, 
however, of late years, received careful attention from 
many able geologists, and it is now ascertained that they 
sometimes contain fossils. 
Thus, some are named “ pre-glacial,” as marking by 
their animal and vegetable remains a coldly-temperate 
climate, and comprise marine sands and gravels, the 
lignite clays, and the forest-bed, with its elephant-remains, 
which are seen cropping out on the Norfolk coast. 
Younger than these, and overlying them—in Norfolk 
at least—come the accumulations of the “ glacial” period 
itself, marked by the Arctic character of its fauna, its ice- 
worn erratic blocks, and its vast deposits of boulder-clay, 
often too feet in thickness, and covering large areas in 
the eastern, central, and northern counties of England. 
It presents most anomalous appearances, the fine clay or 
“till” being unstratified and mostly devoid of fossils, but 
containing rounded and angular fragments of rock, having 
one or more of their sides ground down and striated. 
The laminated beds which accompany the “till” in Nor- 
folk are highly contorted, and much false-bedding and 
irregularity exists in their mode of deposit. To these 
succeed the “post-glacial” period, marked by a more 
temperate climate, and represented by deposits which 
have been formed since the land assumed its present 
level, or nearly so; including lacustrine and river-sedi- 
ments, turf-moors, ancient forests—sometimes converted 
into peat-bogs, and now again reclaimed by man ; valley- 
sediments, resulting from meteoric causes, and, in fact, all 
the most modern surface-deposits, including remains of 
man and his works. 
Although what we have already said about the direct 
connexion between the soil and the sub-soil does relate to 
the regularly stratified deposits, such as the Chalk, the 
Oolite, Lias, New Red sandstone, &c., yet it is found by 
careful observation that those modern and superficial 
patches of clays, sands, and gravels scattered over the 
face of the country far and wide, take such an important 
part in modifying the general character of the soil, that 
to the agriculturists of some districts, they actually 
surpass in interest and importance the more regular 
geological formations of the country. 
When the Geological Survey of Great Britain was first 
undertaken, more than thirty years ago, the Director- 
General had to consider and decide which would be the 
most desirable plan to pursue,—whether to show on the 
geologically-coloured maps these “detrital” or “super- 
ficial” deposits, lying upon and concealing the more 
regularly stratified formations, or only to map the latter ; 
and bearing in mind the fact already stated, that only the 
most vague notions existed in the minds of the earlier 
geologists as to the age or origin of these later deposits, 
and that they were commonly looked upon as the result of 
the deluge ; it is easy to see that there were at that time 
good grounds for their omission. It can, however, readily 
be shown that, from an economic point of view, these 
deposits deserve to be mapped, in the interest of the 
farmer, with as much accuracy as the older rocks have 
been for the miner. 
The advantages to be derived by the farmer from the 
mapping of all surface-deposits—irrespective of age or 
mode of occurrence—are exemplified in the pages of the 
last number of the Journal of the Royal Agricultural 
Society, in which the system commenced many years ago 
by the Council of that Society, and carried out so ably 
on their behalf by Mr. Joshua Trimmer, of making 
reports upon the agricultural geology of lands in various 
districts of England, has been again resumed. In this 
instance, most of the reports are the result of personal 
