[Footnote 241: These rocks were mapped as tuffs by Mr. Ward. Their microscopic characters have been described by Messrs. Harker and Marr, _Quart. Journ. Geol. Soc._ xlvii. (1891), p. 292; by Mr. Harker, _op. cit._ p. 517; and by Mr. W. M. Hutchings, _Geol. Mag._ 1891, p. 537; 1892, pp. 227, 540.] Another type of andesite has been found by Mr. Hutchings to occur abundantly at Harter Fell, Mardale, between the Nan Bield Pass and High Street, and in the cliffs on the right side of the Kentmere Valley. It consists of rocks mostly of a grey-green or grey-blue colour with resinous lustre and extremely splintery fracture. They are augite-andesites of a much more vitreous nature than the dominant type of lavas of the Lake District. Their groundmass under the microscope is seen to have originally varied from a wholly glassy base to an intimate mixture of glass and exceedingly minute felspar-microlites. This groundmass is permeated with chlorite in minute flakelets, and encloses numerous porphyritic sharply-defined felspar-crystals, together with chlorite-pseudomorphs after augite.[242] Gradations from these rocks to the ordinary more coarse-grained andesites may be observed. [Footnote 242: Mr. Hutchings, _Geol. Mag._ 1891, p. 539. This observer describes a quartz-andesite or dacite from near Dunmail Raise.] Some of the andesites appear to have a trachytic facies, where the felspars of the groundmass consist largely of untwinned laths and appear to be mainly orthoclase.[243] [Footnote 243: _Op. cit._ p. 543.] Among the lavas of the Lake District there occur many which are decidedly more basic than the andesites, and which should rather be classed among the dolerites and basalts, though they do not appear to contain olivine. These rocks occur at Eycott Hill, above Easedale Tarn, Scarf Gap Pass, Dale Head, High Scawdell, Seatoller Fell and other places. Analyses of those from Eycott Hill were published by Mr. Ward, and their silica percentage was shown to range from 51 to 53·3.[244] The microscopic characters of the group have been more recently determined by Mr. Hutchings[245] and Messrs. Harker and Marr.[246] [Footnote 244: _Monthly Microscopical Journal_, 1877, p. 246.] [Footnote 245: _Geol. Mag._ 1891, p. 538.] [Footnote 246: _Quart. Journ. Geol. Soc._ vol. xlix. (1893), p. 389. Mr. Harker, _op. cit._ vol. xlvii. (1891).]