Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/834

 and trap. It is an extremely hard, compact rock, and is apparently altogether devoid of cleavage. The red breccia is surmounted by a series of green breccias, ashy beds, amygdaloids, and a few trappean bands, which form the mass of Wallow Crag, the whole being overlain by a fine purple or green porphyritic trap. To the south of Wallow Crag a synclinal fold appears to occur ; and a similar series of breccias and ashes is found in the lower portion of Falcon Crag, near Barrow, dipping northwards at very low angles (about 10°). Forming the summit of the Falcon Crag and the western end of Castlerigg Fell, is a felspathic trap which is nearly horizontal, or has a slight northerly inclination, and appears to be the same as the trap on the summit of Wallow Crag. Still further to the south, between Ashness and Watendlath Beck, an anticlinal fold is formed, and the same strata are again exhibited. Here the lower red breccias are seen nearly horizontal and overlain by the green breccias, both folding over ultimately towards the south, but at extremely low angles. The bedding is very well displayed, and the breccias continue to be visible till Watendlath Beck is reached. Here a fault seems to come on, running in an E.N.E. and W.S.W. direction, across the southern end of Ashness Fell. The evidence of this fault is found in the occurrence again of the lower members of the Green-slate series in the lower part of the Watendlath valley. Between Lowdore Inn and the Waterfall are seen the Skiddaw Slates, a good deal twisted and broken. These are overlain by a massive dark-green felspathic trap, which forms the northern end of Brown Dodd, and over which Watendlath Beck is precipitated to form Lowdore Waterfall. This trap continues up the stream for some distance ; and is succeeded at Thwaite House by a series of cleaved green breccias, with some trappean beds, the former having a vertical cleavage, and the whole dipping S.S.E. at 20°. With the higher part of the Watendlath Beck I am not well acquainted ; but at the village of Watendlath, about a mile and a half above Lowdore, there comes on again a great series of slates and breccias, also with a southerly dip, so that it is most probable that a second E.N.E. and W.S.W. fault produces another repetition of the same beds.

The probable relations of the. lower members of the Green-slate series in this intricate district are shown in the subjoined sketch section from Keswick to Watendlath (fig. 2). Whether this is strictly correct in all particulars or not, it appears quite certain that the following relationships exist between the beds in Borrowdale and on the east side of Derwentwater : — 1. The trap of Castle Head is the lowest member of the series, and is the same bed which occurs at Lowdore, this in turn being identical with the trap of Grange Fell and the Hollows in Borrowdale, and of Dale Head in the Gatesgarth valley. 2. The massive red and green breccias which are seen in Wallow Crag, Falcon Crag, at Barrow Waterfall, and at Ashness are the equivalent of the great slate-band of Borrowdale and Honister. The slaty cleavage is only partially developed, and is sometimes absent ; but in other respects the rocks are the same, and they correspond to each other in stratigraphical position. 3. The trap