OF SOUTH LANCASHIRE. 433 
parallel to the direction of the fault, near 
Ringley. 
In addition to the changes of position of the 
carbeniferous rocks, in consequence of faults, the 
thickness and the structure of the various strata 
are liable to constant modifications, in different 
localities, in South Lancashire. 
Some of the beds occasionally thin out, ot 
they increase in thickness; others vary in their 
mineral structure, and are only identified with 
each other, by the strata which are associated with 
them. 
Specimens of the mineral structure of the 
South Lancashire coal district, are presented 
in the following sections, which have been col- 
lected in different parts of the coal field, by various 
individuals, who have contributed them in a most 
friendly manner, while they have at the same 
time materially assisted the author of this paper 
in the illustration of those portions of the district 
with which they were, from local experience, 
intimately acquainted. 
Nearly all the towns of South Lancashire are 
indebted for a large amount of their manufac- 
31 
