116 LEPIDOPTERA OF BURTON-ON-TRENT AND NEIGHBOURHOOD. 
In the first place there is a vad/ey area of over 300 square miles, 
watered by the Trent and its tributaries—the Derwent, Dove, 
Tame, and Soar. 
Secondly, with Burton as a centre, there are the following 
elevated areas :—Needwood Forest, on the north-west, about 
thirty square miles of well-wooded land, from 300 feet to 500 feet 
above sea-level. Cannock Chase, a heather-covered upland, 
about twenty square miles, from 350 feet to 600 feet, lies still 
more to the west. Charnwood Forest, in the east, is a rocky 
district, of some twenty square miles, irregular in outline and 
elevation, rising in parts, such as Bardon Hill and Breedon to as 
much as 800 feet. The Weaver Hills, 800 feet, and Thorp Cloud, 
in the north, are really portions of the great limestone plateau of 
Derbyshire. 
The prevailing geological formation is New Red, both Bunter 
and Keuper being represented, the former chiefly as Middle 
Bunter—the mottled sandstone occurring but sparingly—the 
latter largely, as Upper Keuper marls and Lower Keuper 
sandstone. 
The great anticlinal of the Pennine Range extends across the 
Trent Valley, causing the inliers of limestone (partially dolomitized) 
at Ticknall and Breedon, and ending with the mass of Archean 
rocks, forming Charnwood Forest. 
There are five coalfields, more or less, included—the whole of 
the Leicestershire and portions of the Warwickshire, North and 
South Staffordshire, and Derbyshire. The soil of much of this 
district is formed from the boulder-clay and drift gravels, but little 
modified by the underlying formations. 
FORMATIONS, ROCKS, ETC. LOCALITIES IN LIST. 
Archean. Charnwood Forest. 
Intrusive greenstone. Bardon Hill. 
Mountain limestone. Dovedale, Ticknall. 
Mountain limestone and Upper Breedon Cloud Wood, Calke 
Keuper marls. Abbey. 
Yoredale Shales and Buntercon- Ashborne and Okeover. 
glomerate and alluvium. 
