HUGHES : INGLEBOROUGH. 
303 
having slid down over a slope of snow which lies long in the 
shelter of these northern precipices, and would linger there 
through the season of early thaw, and, consequently, of the 
chief falls of rock (see Fig. 9). The result of the summer's 
weathering also is seen in a talus close to the foot of the cliff. 
The height of Ingleborough is 2,373 feet above Ordnance 
Datum. Simon Fell is a little over 2,100 feet. Kear the line of 
the section the base of the Mountain Limestone on the Ingleton- 
Weathercote road is at the 800 feet contour, and, taking the 
shortest Hne to the top of Ingleborough, we cross the top of the 
Great Scar, including the Black Shaley Limestone and the 
Black Marble, on the 1,400 feet contour, giving a thickness 
of 600 feet for the Great Scar. We reach the top of the Yoredale 
rocks on the 2,250 line, which gives 850 feet for the Yoredale 
rocks, leaving 123 feet for the Millstone Grit, including the 
flaggy beds above the coarse grit and the sandstone at its base. 
The principal source of error in this estimate is in the fact 
that the base of the Carboniferous rocks is falling fast to the 
north across the line of our section, so that a slight shift in its 
direction would give somewhat different results, and perhaps 
these measurements give too low a figure for the thickness of 
the Great Scar Limestone and of the Yoredale rocks, but they 
furnish a fair approximation which can be easily checked by 
similar traverses up other sides of the mountain. 
Fig. 9. 
