248 
The second range of diluvium to be described is a long 
narrow tract of gravel, which touches the northern drift 
before described, near the river Humber, extending down 
the rivers Aire and Calder, from Leeds, by Ferrybridge, 
to Goole, and about one to two miles in breadth. The 
pebbles are derived from totally different rocks to the last 
described, and are composed nearly altogether of the sand- 
stones of the coal district of Yorkshire, intermixed with 
occasional fragments from the mountain limestone district 
of Craven. This gravel does not extend much north or 
south of the valleys of the Aire and Calder. Leeds stands 
upon it, and beds of it are found on the higher grounds near 
Rothwell Haigh, Oulton, &c. ; and passing through the 
magnesian limestone at Ferrybridge, it is much mixed with 
the detritus of this rock. Pebbles of gannister or galliard, 
with fossil stigmaria, also the mountain limestone, as well 
as the character of sandstones, all belonging to the coal 
district, fully attest the direction of the currents, which, 
from west to east, have transported the materials of which 
this tract of gravel is composed. Its age and origin I will 
examine subsequently. 
A little further southwards, and down the course of the 
river Don, another similar east and west range of gravel 
is found, extending from Doncaster eastwards, by Armthorp, 
Sandal, Thorne, to the south banks of the Humber. This 
tract is about two miles broad, extending over the back of 
the limestone, southwards, to Loversall, and changing the 
agricultural character of the soil. The pebbles of this 
tract of gravel are, in like manner, derived chiefly from the 
harder sandstones of the coal district, especially from the 
salmon-coloured rocks near Rotherham, together with others 
from the mountain limestone of Derbyshire. 
The next tract of diluvium is the one more peculiar to 
Nottinghamshire, of which the first trace is seen, perhaps, 
