in Northumberland and Durham in 1887. 
587 
eastwards by Rothburv to the sea at Warkwortb. The Alne 
has a short course from the hills near Alnham, a few miles 
north of Rothbury, by Alnwick to Alnmouth. The Till, called 
in its upper course the Breamish, is an affluent of the Tweed, 
which it joins near Twizell. This river also rises in the centre 
of the Cheviots ; for about 12 miles it flows eastwards, it then 
runs northwards past Chillingham, and thence in a N.W. direc- 
tion by Woolcr to the Border. A few miles below Wooler it 
receives the Glen, which gives its name to Glendale ward, the 
district which Mr. Grey selected as exhibiting the best examples 
of the turnip course of husbandry.* The Tweed is a Scotch 
river until within 16 miles of the sea. From Carham to Tweed- 
mouth it divides England from Scotland. 
Geology. — The principal geological features of the county are 
as follows. 
' The Coal-measures occupy a triangular space in the S.E. of 
the county. This triangle has its base on the Tyne, and its 
apex near Warkworth. Its eastern side is the sea, and its 
western side extends from Warkworth by Morpeth to Heddon- 
on-the-wall. 
" There are also some detached coal-measures stretching from 
the main mass to the west into Cumberland." f Within this 
area are found no less than 20 valuable seams of coal, besides 
many minor beds of superior quality. 
There are said to be 176 collieries in the county, and the 
output of coal is about 14 millions of tons in a year, and is 
continually increasing. 
The greater part of this district is covered with boulder clay 
intermixed with deposits of sand and gravel. The surface is 
generally flat, and the soil intractable. 
Fringing the coal-measures on the west is a narrow band of 
Millstone Grit, never exceeding 7 miles in width. This forma- 
tion consists of sandstones, shales and coals, and is described by 
Prof. Lebour as " having no distinctive fossil remains and 
nothing peculiar to it but its position." J 
To the west and north-west of the millstone grit is a broad 
band of Carboniferous Limestone, variously classed by different, 
geologists and named by Prof. Lebour as Bernician, as ex- 
pressing the peculiar character of the carboniferous limestone 
in Northumberland, the ancient Bernicia. The great lime- 
stone bed of this series is quarried everywhere throughout its 
course, and yields lead largely in the western mining district. 
Parallel to it runs a band of sandstone, much used for building 
* 'Journal of the Koyal Agricultural Society,' vol. ii. p. 157 (1841). 
t Lebour, ' Geology of Xorthumbcrland and Durham.' % Ibid. 
