50 
VAUGHAX : THE KXOLL REGION OF ("LITHEROE, ETC. 
(Tlie period being the same in both cases, viz. the A'iseau or Upper 
Avoiiian). The conclusion that there is a great and sudden change of 
thickness at the fault-belt remains therefore quite as obvious as was 
originally pointed out by Mr. Tiddeman. Furthermore, it is difficult 
to conceive how this progressive increase of depth-dift'erence on the 
two sides of the fault-belt could have been brought about, except by 
the depression of the Southern Region relatively faster than that of 
the North ; in other words, by the initiation and working of the Craven 
faults already in Lower Carboniferous-time.) 
CONCLUSION. 
Although the large Knoll Region of Clitheroe, Rowland and Craven 
has yet many secrets to yield up, it is to Mr. Tiddeman that we owe 
the firm foundation of our knowledge. 
With the help of Prof. E. J. Garwood's valuable description of 
the N. W. Province, we shall find it easy to extend the correlation 
in that direction. 
To recent work we owe the fact that the broad datum-lines 
of the time scale are now firmly established. There is however, all 
the detailed palaeontology yet to do, and, for this purpose, collecting 
must be thorough and unsparing. It is therefore to local workers- 
that we look for further progress and in particular to Dr. A. Wilniore,, 
of Colne, who has already commenced a detailed zonal survey of the 
whole region West and North of Pendle. 
For my knowledge of the district, I am largely indebted to Dr. 
Wilmore's ready assistance on the occasions of my short visits ; but 
above all to the demonstration and explanation of Mr. R. H. Tiddeman, 
my long-time friend and ever kind instructor, to whose inspiration 
this brief note owes whatsoever it posseses of use or merit. 
[We much regret to record that before this paper was printed^ 
the talented author died prematurely. His loss is a great one to 
geology in general, and to Yorkshire geology in particular]. — Ed. 
