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old valley, — that is to say, in a long trough extending between the 

 Cross Fell Escarpment, or Black Fell Side, as old people call it, 

 and the Lake District, which the same people call by the name of 

 the West Fells. According to this view, the area at present occu- 

 pied by the Red Rocks nearly or quite coincides with the original 

 area of deposition. I believe that this view will not bear a close 

 examination. If we take a series of measurements downward from 

 the first persistent stratum in the Red Rocks to the local base, 

 from one end of the area covered by the Penrith Sandstone to the 

 other, we get, as it were, a series of soundings, which enable us to 

 reconstruct exactly the form of the old surface along that line. 

 From the north-western end of the Penrith Sandstone area in 

 Galloway, to its south-eastern termination near Stainmore, is between 

 fifty and sixty miles. Now, the greatest thickness of strata accumu- 

 lated below the first uniform bed along that line, — in other words, 

 the lowest depression below the general level of the surface along 

 that line — nowhere much exceeds a thousand feet. This gives us 

 a rise of about one in four hundred between the lowest point we 

 know anything about, and the highest-known portion of the old 

 surface, — a gradient so low, that it is practically inappreciable. 

 This, of course, is along the line of the supposed old valley. 

 Transverse to this direction, i.e. across this supposititious valley, 

 it is important to bear in mind that there is very little but negative 

 evidence to go upon. Outliers of Penrith Sandstone on the Lake 

 District side of its principal area are almost entirely unknown ; so 

 that between the valley of the Petteril and the Lake District, 

 except about Highet Castle and Raughton Head, there is hardly 

 any information attainable bearing upon the form, and the extent, 

 of the surface that was once covered by the Penrith Sandstone. 

 Along the edge of the Cross Fell Escarpment we sometimes get 

 the Penrith Sandstone turned up on edge against the Pennine 

 Faults, so that we thus have an opportunity of examining a bed of 

 rock that is usually at a depth of many hundred feet from the 

 surface thereabouts. It is important to observe, that in no instance 

 of this kind does the rock present any appearance of being nearer 

 to a shore line there than it is elsewhere ; nor does it in any other 



