Paleo-Geological and Geographical Maps of the British Islands. 293 
the area referred to. From this red mud a deposit would be formed similar to that 
of the upper boulder clay of Lancashire, Cheshire, North Wales and Ireland, the 
Hessle clay of Yorkshire,* and its representatives in the north-east of England. 
This deposit consists of reddish clay, slightly laminated, and containing bands of 
sand or loam. In some places it contains foreign stones and small boulders brought 
from a distance, and in a few instances marine shells have been detected in it. Thus 
at Gorton, near Manchester, the following rock fragments, nearly all foreign to the 
neighbourhood, were determined some years ago :—t 
Silurian grit, . ‘ 0 5 . 37 per cent. 
Felspar porphyry, . ; ° . MLO) OF 
Felstone, . : ‘ 
Carboniferous grit, , q : wil. 
Granite, ; 
Porphyritic agglomerate, 
Carboniferous limestone, . 
ro WwW Ee S ~e bo 
Ironstone, . : : ° 
| 
(Ne) 
eo) 
? 
The majority of the above specimens had evidently been transported from the 
district of Cumberland and North Lancashire, which we may suppose sent off loads 
of stones and boulders southwards upon ice-bergs and rafts. 
The upper boulder clay rises to elevations of 500-600 feet amongst the western 
slopes of the Lancashire hills, and marine shells (Turritella terebra, Fusus Bamjfius, 
Purpura lapillus, &c.) have been found in it; as, for instance, at Hollingworth 
Reservoir (568 feet above the sea), the vale of Mottram, Bradbury and Hyde. 
From this elevation it gently slopes southward and westward, towards the plain of 
Cheshire,§ which is largely overspread by it ; it occupies portions of the low valleys 
of North Wales.|| On the other hand, the Pennine table-land of South Yorkshire and 
North Derbyshire, and the low country to the east of it are free from drift deposits, 
a state of things very difficult to explain, but clearly indicating the absence of glacial 
conditions amongst the eastern valleys of the Pennine chain south of the parallel 
of 53° 35' N. lat. 
* This is described by Mr. 8. J. Wood as a deposit of clay containing a few scattered stones and 
boulders when the sea extended over the land to an extent not exceeding 350 or 400 feet anywhere in 
Yorkshire. Geol. Magazine, vol. vii. 
+ By Professor Ramsay and the author. “Geol. of Oldham, é&c.,” Mem, Geol. Survey (1864). 
{ By Mr. Bateman, c.z., Professor Prestirch, and Mr. John Taylor. “Geol. of Oldham, &c.,” Mem. 
Geol. Survey (1864), p. 51. 
§ “Geol. of North Derbyshire.” Jbid, p. 75. 
|| In a pit by the railway side, near Abergele, it may be observed capping the interglacial gravels at 
an elevation of only 20-30 feet above high water. 
{1 “Geol. of Dewsbury, &c.,” Mem. Geol. Survey, p. 20 (1871). 
