1907-8.] Classification of Igneous Rocks. 101 
— continued. 
O. Nordenskjold, B. G. Inst. Un. Upsala , i., 
p. 216, 1894. 
G. F. Becker, M. xiii, U.S.G.S. , p. 159, 1888. 
Q. Journ ., 1895, p. 141. 
N. Jahrb ., 1904, vol. ii., p. 403. 
Watt’s Dictionary of Chem. 
Weed and Pirsson, B. U.S.G.S ., 139, p. 96, 1896. 
A. Lagorio, T.M.P.M. viii., p. 444, 1887. 
N. Jahrb., 1899, suppl. 12, p. 162. 
P. Marshall, Tr. N.Z. Inst., xxvi., p. 379, 1894. 
A. Lagorio, Guide. Exc. vii., Conq. G. Int., 
xxxiii., p. 27, 1897. 
Rhyolite (Halleflinta). 
Rhyolite obsidian. 
Skiddaw granite. 
Aplite. 
Pumice. 
Aplitic granite. 
Obsidian. 
Granitite. 
Tridymite trachyte. 
Keratophyre. 
Sweden. 
Borak Lake. 
Whitegill. 
Atlanta, Georgia. 
Cotopaxi. 
Montana. 
Ecuador. 
Querseifen. 
N. Zealand. 
Russia. 
N. Jahrb., 1904, vol. ii., p. 407. 
N. Jahrb., 1904, vol. ii., p. 223. 
Q. Journ., 1893, p. 558. 
AT. Jahrb., 1899, suppl. 12, p. 232. 
C. Barrois, Guide , Exc. viii., Cong. G. Int., vii., 
p. 21, 1900. 
H. W. Turner, 17, A. R. U.S.G.S ., i., p. 702, 1896. 
N. Jahrb., 1901, suppl. 14, p. 38. 
J. B. Harrison, priv. contrib. 
N. O. Holst, Ahr. Sver. G. Und., No. 110, 
p. 37, 1890. 
Merrill, p. 207. 
Q. Journ., 1906 (Dr Evans), p. 119. 
N. Jahrb., 1904, vol. i., p. 49. 
N. O. Holst, Abh. Sver. G. Und., No. 110, 
p. 37, 1890. 
Quartz porphyry. 
Quartz diorite porphyrite. 
Porphyritic felsite. 
Granitite. 
Granite. 
Biotite granite. 
Porphyroid. 
Granitite gneiss. 
Rhyolite. 
Granite. 
Granite. 
Porphyry (dark). 
Rhyolite. 
N. Hampshire. 
Montenegro. 
Arran. 
Riesengebirge. 
Bretagne, France. 
Amador county. 
Harz. 
Br. Guiana. 
Sweden. 
Columbia. 
Madeira, S. America. 
Bohulibi. 
Sweden. 
N. Jahrb., 1902, vol. ii., p. 237. 
A. Benard, Challenger Reps. Pet. Oc. Islands, 
p. 52, 1889. 
N. Jahrb., 1904, vol. ii., p. 403. 
N. Jahrb., 1904, vol. ii., p. 406. 
JSf. Jahrb., 1900, vol. ii., p. 221. 
Q. Journ., 1895, p. 178. 
Q. Journ., 1895, p. 129. 
H. S. Washington, J.G., vii., p. 293, 1899. 
Bf. Jahrb., vol. ii., p. 221. 
N. Jahrb., 1901, vol. i., p. 242. 
Q. Journ., 1895, p. 178. 
A. Geikie, p. 141. 
Quartz keratophyre. 
Obsidian. 
Granite. 
Quartz porphyry. 
Quartz porphyry. 
Pot. soda felsite. 
Granophyre. 
Keratophyre. 
Rapakiwi porphyry. 
Biotite granite. 
Liparite. 
Obsidian. 
Massachusetts. 
Ascension Island. 
Atlanta. 
N. Hampshire. 
Storflasen. 
Carn Gelli, Fishguard. 
Carrockfell. 
Massachusetts. 
Rodon. 
Yosemite Valley. 
Island of Ponza. 
Average. 
