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upper ones at Cayton Gill; in most other cases, however, 
only one bed is traceable. The formation extends westward 
as far as Pateley, northward as far as Sawley, and southward 
as far as Hampsthwaite ; I am not able to say how much 
further it extends in these several directions, but I am 
inclined to think that it does not reach much further to the 
north or south ; and that it is only a local deposit in a narrow 
arm or estuary of the carboniferous sea. The fossils most 
frequently found, but which in many cases are represented 
only by casts, are Orthis resupinata, 0. michelini, Producta 
semi-reticulata, P. aculeata, Spirifera lineata, S. trigonalis, 
Spiriferina octoplicata, Chonetis hardrensis. 
Arenaceous Flags and Coal Measures. — Immediately below 
these beds is a series of shales, flags, and sandstones, of con- 
siderable thickness ; all more or less stained with iron. Some 
of the upper beds of flags contain many various and interest- 
ing shore markings, tracks of Worms, Mollusca, &c. 
In the lower beds there are one or two thin seams of coal, 
but they are not of sufficient value to pay the cost of working. 
Several shafts have been sunk in various places, but they 
have all been abandoned as unprofitable. 
The whole series rests upon the Scar limestone. 
The highest point of the district under consideration is at 
Brimham, from which three ranges of hills sink down in an 
easterly direction, until they are crossed by the low range of 
the Magnesian limestone. 
The valleys which lie between these hills owe something of 
their form to the forces of elevation, which have thrown the 
strata into folds and waves flowing from north to south, 
interrupted at Scarah Bank and Killinghall by two faults : 
but most of their configuration is due to denudation. As 
they ascend from the lower districts they grow narrower, 
and more picturesque, and are generally well wooded. One 
of the prettiest of these valleys is the one at the head of 
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