437 
THE OCCURRENCE OF LIMESTONE CONGLOMERATES ON THE NORTH SIDE 
OF THE CRAVEN FAULTS. BY R. H. TIDDEMAN, M.A., F.G.S., OF H.M. 
GEOLOGICAL SURVEY. 
(Read November 7 th, 1894.) 
(Communicated with the permission of the Director General of the 
Geological Surveys of the United Kingdom.) 
In 1890, when the British Association met at Leeds, at the 
request of the Local Committee I drew up a description of the 
" Physical History of the Carboniferous Rocks of Upper Airedale," 
which appeared in the Local Handbook presented to the visitors. 
Through the instrumentality of your late Secretary, Mr. Jas. W. Davis, 
this paper was rescued from the limbo of so ephemeral a publication, 
and printed in the Proceedings of your Society (vol. xi. part iii). 
Amongst other things it called attentiou to the great discrepan- 
cies in the Lower Carboniferous Rocks on either side of the Craven 
Faults, and showed that these different types, which were called the 
Bowland and Yoredale types, extended, the one from the plains in 
Lancashire bordering the Irish Sea to the Craven Faults, and the 
other from those faults away to the Scottish border. It was pointed 
out that these two distinct types showed no tendency to assimilate 
at the line of junction, but were if anything still more pronounced 
there. 
The enormous thickness of the rocks on the Bowland, south, or 
downthrow side of the faults (as compared with the Northern or 
Yoredale type) was regarded as evidence that the faulting was going 
on concurrently with the growth of the deposits on that side.* 
Further, an attempt was made to sketch out the geography of 
the Carboniferous seas in the North of England at that early period. 
A moderately full description was given of the " Knowl Reefs " of 
the country on the south side of the Craven Faults. These are great 
mounds of white limestone made up of organic remains, such as 
Brachiopods, Lamellibranchs, Gasteropods, Crinoids, and Corals. 
* See also paper by the author, " On Concurrent Faulting and Deposit 
in Carboniferous Times in Craven, Yorkshire, with a note on Carboniferous 
Reefs. Tran. Brit. Assoc., Xewcastle-upon-Tyne, 1889. 
