THE WEST OF ENGLAND AND EAST OF WALES. 439 
Il. Tue great CumBerLAnp GRANITE- AND FELSTONE-DISPERSION. 
1. Boulder-supplying capacity of the Lake-district— Commencement 
of the Dispersion.—Boulders of felspathic rocks varying from coarse 
breccia, tuff, or ashes to compact felstone may have gone south from 
almost any part of the Lake-district situated between Wasdale Crag 
(Shapfell) and the western boundary of the Cumberland mountains. 
Though numerous boulders have gone south from the eastern or 
Westmoreland part of this area, I do not think that many of them 
(east of the river Leven) have found their way far enough south- 
west to become incorporated with the great Cumberland and Kirkcud- 
brightshire dispersions, Many boulders of felspathic rocks, more or 
less accompanied by fine-grained syenite, must have gone south from 
the heights around Wastwater and Ennerdale. Initial concentrations 
of them may be seen near Gosforth and Drigg. Lake-district-felstone 
boulders have been more generally and numerously distributed than 
the granite boulders, though they never occur alone in the form of 
great terminal concentrations. In the Eskdale-granite area there 
are now many loose blocks so situated that were it again to become 
submerged beneath an icy sea, they would probably follow the ex- 
ample of their erratic predecessors. Though this area is much 
smaller than the Criffel area, the ground is much more broken and 
varied, so as to furnish a greater number (in proportion to its size) of 
transportable blocks. Mr. Aveline (of the Geological Survey) informs 
me that very little of the Eskdale-granite area rises above 800 feet ; 
and this confirms the idea (already broached) that the main part of 
the Eskdale dispersion took place before the land had become deeply 
submerged, and probably before the setting in of the great southerly 
extension of the Criffel dispersion. Some parts of the Eskdale- 
granite area, however, exceed 800 feet—for instance, near Devoke 
Water, 1049 feet, and south of the south-west end of Wastwater 
Screes escarpment, 1286 feet. The latter altitude is rather more 
than that of the highest Hskdale-granite boulder I have yet seen, 
but not so high by about 100 feet as the Eskdale pebbles in gravel 
near the summit of Moel-y-Tryfaen. Allround the mouth of Eskdale, 
and south in the direction of Bootle, the granite blocks are thickly 
congregated, and a number of large ones may be found on the west 
side of Blackcombe Mountain, nearly 1000 feet above the sea, which 
may have gone from Rough Crag, north of Devoke Water(?). The 
boundary of the commencement of the dispersion runs along a line 
drawn from near Irton to a little west of Drigg. Between this line 
and the east boundary, which runs along the west side of Blackcombe, 
the dispersion radiates until it is lost under the sea*. 
2. Dispersion to North Wales.—Boulders and pebbles of Eskdale 
conjecture, from microscopic examination only, the geologic age of an igneous 
rock ; but on the whole it seems to me not improbable that this specimen may 
be of Miocene age. JI am not sure how far south these rocks haye been 
traced along the west coast of Scotland.” 
* Hskdale granite has generally white or pale pink felspar, very watery- 
looking quartz, and little or no black shining mica, though silvery mica is some- 
times present. It is often ¢énged of a reddish hue, Most of it is coarse-grained. 
