WILLIAM SMITH : HIS MAPS AND MEMOIRS 119 
intended for the Under Oolyte." The " Freestone " follows. The 
greatest heights are *' 1,134 [feet] near Cheltenham " and " 883 
Stow on the Wold." The " Vale of Isis " is next, with " Forest 
Marble,'' " Coriibrash," " Clay,'' " Sand," " Limestone," and " Sand " ; 
then " Chalk," and, in the " Vale of Thames " Brickearth " and 
" London Clay." 
The Strata all dip to the South-east, the dip being at a less angle 
as the low ground is reached. The formation of the valleys and escarp- 
ments is clearly shown. 
In the space to the west of the Bristol Channel is the following 
*' Explanation " : — 
I I * London Clay of Harroio, Highgate and Shooters Hills. 
J I Clay and Brickearth, with some Sand and Gravel. 
I I Sand and Light Loam . 
r I Chalk. 
j ^1 Green Sand, parallel to the Chalk. 
I ~ Bhie Marl, or Oaktree Soil. 
I I Purbeck Stone, Kentish Rag, and Limestone of the Vale 
of Pickering. 
I I Iron Sand or Carstone. 
I Clunch Clay or Shale, Vales of North Wilts, and 
Bedford. 
I Cornbrash Limestone. 
I I Forest Marble and Clay. 
I I Great Oolyte or Bath Freestone. 
I [ Under Oolyte. 
I j Blue Marl Pastures of the Midland Counties. 
I I Blue and White Lias Limestones. 
* These tablets are coloLired on the original to match the colours 
on the Map and Section. 
