GENERAL VIEWS. 
177 
stones grow much thinner, and are almost lost in a mass of plates, while 
upper terms of the series appear. In Ingleborougli the whole thickness 
is much augmented, but the limestones are still obscure, except the 
lowest and the uppermost : an equal thickness of beds appears in Wharn- 
side, and the limestones are all complete ; (the upper one thin.) In Bar 
fell the Yoredale series appears to be about 1000 feet thick, and all 
the limestones are seen except one of the upper beds. This thickness, 
all the limestones being complete, continues through Swaledale ; but 
in the lower part of Wensleydale and Coverdale it rapidly contracts ; 
the lower limestones thickening and the upper ones, with the greatest 
part of the grits and shales, growing thinner as the section approaches 
Great Whernside. These circumstances are represented in the diagram, 
which thus shews that in the direction where the lower group, con- 
sisting wholly of limestone, thickens, the Yoredale rocks, consisting 
chiefly of gritstones and plates, grow continually thinner. 
The millstone grit series does not appear liable to so great variations 
of thickness as those just described : the very detached manner of its 
occurrence is also unfavourable to exact results. The lowest portion 
of the deposit may however be noticed. The Ingleborough millstone 
grit is almost in contact with the top of the Yoredale series in the 
vicinity of Great Whernside ; but in leaving this point in any direction 
there is found an intervening set of plates, limestones, cherts, and some- 
times coal, amounting to 40, 60, 100, and 120 feet in thickness. This 
circumstance is introduced into the diagram ; which thus shews at a 
glance the principal features of the variation of thickness, &c. in the 
district; and indicates, as a general result, that the intensity of the 
agencies which produced the lower or Wharfedale limestones aug- 
mented toward the south-east, and diminished toward the north-west, 
while the agencies predominating in the production of the Yoredale 
series diminished toward the south-east, and augmented toward the 
north-west. 
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