Harker: Chemical Notes on Lake District Rocks. 153 
(108). 44°44. Mica-lamprophyre, ed eeen ites 34 mile from 
Windermere Statio 
(109). 32°31. Mica-lamprophyre, Helm Gill, near Sedbergh, 
lowest dyke; a much decomposed rock. 
(110). 47°2. Mica-lamprophy re, Helm Gill, ‘the most 
southerly dyke. 
(111). 47°1. The same, duplicate analysis. 
(112). 46°34. The same, another specimen. 
(113). 58°99. Mica-lamprophyre, E. bank of Doe, Storrs, 
Ingleton. 
These last four analyses have not been published, and are 
accordingly given in full below. Since Mr. Tate’s chemical 
work on the, Yorkshire lamprophyres seems otherwise to be 
lost,* I am glad to be able to preserve a portion of it here. He 
had further made analyses or partial analyses of a variety of 
rocks from the Lake District proper, and intended? to give the 
results in this journal, but that design was never carried into 
effect. In analyses (110) to (112) the ‘difference’ represents 
water and carbonic acid. Since these constituents are not likely 
to be negligeable in a rock of this group, it is se Sag that 
analysis (113) was made on material already ignit 
(r42) (113) 
Helm Gil, Kiel Gill, Helm Gill. heotens 
Silica = po ME APA ee BOA I RBG 
Alumina ... Ie a IO a MOM 6G 
Ferric oxide Sy aR eee SB Biel <n Re ng eae 
Ferrous oxide)... = eee Elen Oo eee eS 
Manganous oxide — 0°25 0°20 
Magnesia. oC se 5 3°54 2°30 
ime oe ra | te | i a 12°73 6°74 
Soda ae ee PS ey 40 4°53 3°78 
Potash : ...: nae eo Pe eae ee ae 
Difference eee LG PRO ee ae 
100°O 100°0 00°00 100 10°64 
There remain only a few analyses of sedimentary rocks and 
their metamorphosed representatives. numerous analyses 
of metalliferous ores scattered through mining literature are 
regarded as outside the scope of our subject, and analyses of 
Minerals are excluded for the same reason. Six complete 
analyses of rocks from the Skiddaw Slate group have been 
published, and their silica-percentages are reproduced below for 
* Proc. Yorks. Geol. Pol. Soc. (N.S.), vol. xiii., p. 352, 1898. 
me mae + Naturalist for 1892, p. 240. 
May 1899. 
