350 T. W. E. DAVID, F. B. GUTHRIE, AND W. G. WOOLNOUGH. 



At S. Antao, however, in the Cape Verde Islands, Doelter 1 has 

 described a phonolitic nephelinite which in mineral constitution 

 appears to approximate closely to the Kosciusko rock. Rosenbusch 

 (p. 1260) describes this rock as being conspicuously green in 

 colour, the nepheline being present in sharply idiomorphic crystals, 

 in which two generations can be distinctly recognised, whereas 

 the sanidine occurs sparingly or more abundantly in small laths 

 (•'Leistchen"), the structure of the rock being evidently porphyritic. 



Sauer 2 has described a nepheline — haiiyne phonolite with pleo- 

 chroic augite, a little hornblende and plagioclase from the Canary 

 Islands, 



Doelter 3 has also described a trachytoid phonolite from the 

 volcano Mount Ferru, in Sardinia, varying from a rock poor in 

 nepheline to one in which the nepheline is in excess of the sanidine. 

 Haiiyne occurs sparingly. 



Deecke 4 has described phonolite dykes in the tuff of the crater 

 walls of Vico in the Ciminian Hills of Italy. Nepheline, sanidine, 

 augite, haiiyne, plagioclase and titanite are present. 



Professor J. W. Gregory, has described 5 nepheline syenites, 

 phonolite dykes and kenyte lavas from Mt. Kenia. The last 

 mentioned consists of a glassy matrix very rich in soda, with 

 granules of segirine, felspar microliths and phenocrysts of 

 anorthoclase. 6 



Rosiwal has described a nephelinite from the Maeru Mountains 

 (Meru-Berg) from S. E, Africa. 7 This contains some brown 



1 Doelter (C), Die Vulkane der Capverden und ihre Produkte. Gratz, 

 1882. 



2 Sauer. Phonolithische Gest. Der Canarischen Inseln, Inaug. — Diss. 

 Halle 1876— Ztschr. f. d. ges. Naturw., xlvii., 1876. 



3 Doelter, Phonolith von Sardmien, Denkschr. Wiener Akad. xxxix , 

 1878, 59. 



* Phonolith von Vico, Italien. N. Jahr. f. Min. Beilageb. vi., 1889, 239. 



5 Gregory (J. W.), Q.J.G.S., Vol. evi., 1900, pp. 205-202 and pis. x., 

 xi. and xii. pars "The Geology of Mt. Kenia," and Q.J.G.S., Vol. evi , 

 1900, pp. 223-229 and pi. xii. pars. "The Nepheline-syenite and Camp- 

 tonitic dykes intrusive in the Coast Series of British East Africa." 



6 See also Min. Mag. Vol. xii.. July 1900, pp. 255-273. "^girine and 

 Eiebeckite anorthoclase rocks related to the Grorudite-Tinguaite Series, 

 from the neighbourhood of Adowa and Axum, Abyssinia," by G. T. Prior. 



7 Eosiwal, Denkschr. Wien Akad. lviii., 1891, 487. 



