No. II. 
Explanation of Colours on the Map of STRATA, taken in Succession 
from East to West, as the Strata occur. 
5) 
12 
13 1 
14 
15) 
16 J 
18 1 
19) 
20 ) 
to 23 / 
London Clay, forming Highgate, Harrow, \ ' 
Shooters, and other detached hills ) 
Clay or Brick-earth, with interspersions of Sand 
and Gravel 
Sand, or light Loam, upon a sandy or absorbent 
Substratum 
rv, 11, i Upper Part, soft, contains Flints 
L-naiK ( Under Part, hard, none 
Green Sand, parallel to edge of Chalk 
Blue Marl, so kindly for the growth of oak as to 
be called in some places the oak-tree soil. 
Purbeck Stone, Kentish Rag, and Limestone of 
the Vale of Pickering. 
Iron Sand and Carstone, which, in Surrey and \ 
Bedfordshire, contains FuUer's-earth, and, in ,- 
some places. Yellow Ochre and Glass Sand. . ) 
Dark Blue Shale produces a strong clay soil, 
chiefly in pasture, in North Wilts and Vale of 
Bedford. 
Cornbrash, 
arable . . 
thin Rock of Limestone, chiefly 
j Magnesian Limestone ) 
( soft Sandstone j' 
Coal districts and the Rocks and Clays which 
accompany the coal 
Generally a Sandstone beneath. 
Derbyshire Limestone 
Red and Dan-stone, of the southern and ncr-" 
thern parts, withinterspersions of Limestone, 
marked blue 
Various. 
Killas, or Slate, and other strata, of the moun- 
tains on the western side of the island with 
interspersions of Limestone, marked blue. . . 
Granite, Sienite, and Gneiss 
Septarium from which Parker's 
Roman Cement is made. 
I' No building Stone in all this ex- 
! tensive district, but abundance of 
I materials which make the best 
^ bricks and tiles in the island. 
I' These strata contain the Potter's 
-i Clay, and Sands used for different 
V purposes. 
Flints the best road materials. 
Good Lime for water cements- 
Firestone, and other soft Stone, some 
times used for building. 
Some Lime used on these Sands in 
Sussex and Yorkshire. 
f 
Forest Marble Rock, thin beds, used for rough 
Paving and Slate. 
Great Oolyte, Rock, which produces the Bath^ 
Freestone 
Under Oolyte, of the vicinity of Bath and the 
midland counties ^ 
Blue Marl, under the best pastures of the midland 
counties. 
Blue Lias Limestone, makes excellent Lime for 
water cements. 
White Lias, now used for printing from MS. 
written on the stone. 
Red Marl and Gypsum, soft Sandstone and Salt n 
Rocks, and Springs. \ 
Makes tolerable roads. 
/The finest building stone in the is- 
J land for Gothic and other archi- 
j tecture which requires nice work- 
\ manship. 
Small quantities of Copper and Lead. 
^ r Grind-stones Mill-stones, Paving- 
^ -| stone. Iron-stone, and Fire-clay 
i"! t from the Coal districts. 
Lead, Copper, and 
minaris — Marble. 
Lapis Cala- 
)1 
Some good building Stone. 
o The Limestone polished for Marble. 
X, Tin, Copper, Lead, and other minerals 
(5 (The finest building Stone in the 
\ island for bridges and other heavy 
i work. 
Alluvial deposits in low marshy grounds around 
the coast are shaded as original inlets of the sea. 
From Smith's "Memoir to the Map," 1815. 
Tv face page 128. 
