Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 Excerpt:...will be seen on referring to the map forming the frontispiece. Leaving minor details out of account, it will be noticed that Britain may be roughly divided into four areas, each occupied mainly by one of the groups. That portion of Scotland which lies to the north-west of a line drawn from the Firth of Clyde to Stonehaven, south of Aberdeen, is largely occupied by Precambrian rocks, and it may be mentioned that this line is continued into the North of Ireland, owing to the occurrence of these rocks in Donegal. The next line to be noticed is one which extends with somewhat sinuous course from the mouth of the Tees to Start Point, in Devonshire. With few exceptions, the rocks occupying the area between this line and that noticed above are referable to the Primary group. These rocks occupy the Central Valley and Southern Uplands of Scotland, the Lake District of England, the Pennine Chain and moors on either side of it, Wales, Devon and Cornwall, and also the greater part of Ireland. A third line is traceable from the coast of Norfolk to the neighbourhood of the Isle of Purbeck. The area between the second and third lines is chiefly occupied by Secondary rocks, which also stretch to the east of the third line in one tract, occupying the Kentish Weald and the North and South Downs, while the rest of the area lying to the south-east of the third line is chiefly covered by Tertiary rocks. From an agricultural point of view the rocks of the earth's crust are important, not only on account of the materials which they furnish for the formation of soil, but also because of their effects in controlling the surface features of the land. Other things being equal, the older the rocks the more durable they will in all likelihood be, for they have been subjected to the var...