18 SCIENTIFIC SURVEY OF LEICESTER AND DISTRICT 
the latter are largely quarried for ironstone to supply the local furnaces 
at Holwell, near Melton Mowbray. 
The eastern margin is formed of typical ‘ wold’ country comprising 
hills of circumdenudation with cappings of soft Upper Lias clay and 
inferior Oolite outliers culminating in Whatborough Hill, near Tilton, 
which reaches a height of 755 ft. above sea-level. The eastern boundary 
of the county descends in a general southerly direction to Great Easton 
in the Welland Valley and then by a south-westerly course along the river 
through Market Harborough to Catthorpe, near Rugby. 
The county boundary then runs along Watling Street, over Triassic 
rocks, to the neighbourhood of Atherstone, and then north-eastwards 
across Coal Measures of the Ashby and South Derbyshire Coalfield, 
Millstone Grit and Triassic rocks to the river Trent at Long Eaton. 
The oldest rocks in this area appear at the surface through the covering 
of Keuper Marls, about six miles north-west of Leicester and about 
three miles west of Loughborough on the west side of the Soar valley. 
These are the pre-Cambrian rocks of Charnwood Forest. 
The highest point is Bardon Hill, 912 ft. high, though several com- 
manding view-points rise to a height of over 800 ft. These include 
Timberwood Hill, Beacon Hill, and Birch Hill. 
The Charnwood Forest sequence consists of a varied suite of pyro- 
clastic volcanic ashes, agglomerates, grits, hornstones, conglomerates and 
slates, which have been divided into three conformable series. The 
oldest, the Blackbrook series, has not been subdivided and consists of 
greyish massive grits interbedded with greyish and greenish hornstones, 
often beautifully banded and heavily stained along the joint faces from 
the overlying Trias. On Ives Head occurs a porphyritic Felsite dyke 
unrelated to any other known rocks of the Forest. 
The Maplewell series consists of tuffs, agglomerates and hornstones 
and comprises several subdivisions, the most striking of which the 
Slate Agglomerate—an andesitic tuff containing fragments of purple 
and green slate—is traceable on both sides of the anticline. 
The Brand series, consisting of conglomerates, grits, quartzite and 
slates, forms the outermost beds, several of which have been formerly 
worked for roofing slates. This industry has now become extinct. 
The Charnwood rocks are stated by Prof. W. W. Watts to be ‘ not 
like the Uriconian or Torridonian rocks unless we except the grits and 
conglomerate of the Brand series, which have some resemblance to 
the Torridonian rocks. On the other hand, they have nothing in common 
with the gneisses and schists of the north-west or central Highlands of 
Scotland. Many of the individual bands are like those of the Longmynd 
in Shropshire, and indeed if we could imagine the pyroclastic materials 
from the Charnwood volcano dropped far from the vent and sorted and 
stratified in water, they would be likely to produce a group of rocks 
much like those of the Longmynd. It is impossible at present to push 
the comparison further, and meanwhile it may be better to be content 
with naming the whole group the Charnian System, and to refer i it to some 
unascertained position in the great pre-Cambrian sequence.’ 
The beds forming the Charnian System were folded by earth move- 
