444 DESCRIPTIONS OF ROCKS. 



and near Cruger's, in the town of Cortland, N. Y., at the 

 latter place often graduating into a granite-like dioryte. 



Kersantyte is described by Del esse as consisting of biotite and oligo- 

 clase, with some quartz, frequently hornblende in needles, and mag- 

 netite ; from the Vosges, the Saxon Erzgebirge, and Nassau. Kersan- 

 ton is a similar rock, containing no hornblende, from near Brest, and 

 from Quimper, in Brittany. Both of these rocks have been called mica- 

 dioryte. 



Kinzigyte is a compact and schistose granular-crystalline rock, con- 

 sisting of biotite, oligoclase, and garnet, without quartz, and contain- 

 ing, as accessory, microcline, iolite and fibrolite ; from Kinzig, north 

 part of Black Forest. 



n. CONTAINING NEPHELITE. 



1. Miascyte. — Granitoid to schistose, and consisting of 

 microcline, massive nephelite (elaeolite), sodalite, biotite, 

 along with some quartz, and often some zircon, pyrochlore, 

 monazite and other minerals. A related nephelite rock oc- 

 curs on Pic Island, Lake Superior. Named by G-. Rose, 

 from Miask in the Ilmen Mountains, where it has a wide 

 distribution. Metamorphic. 



2. Ditroyte. — A coarse to fine-grained rock, consisting of 

 microcline, nephelite (elaeolite), and sodalite. From Ditro in 

 Eastern Transylvania, where it is associated with syenyte 

 and mica schist and lies between these two rocks. 



3. Phonolyte. (Clinkstone.) — Compact; of grayish, blue, 

 and other shades of color ; more or less schistose or slaty in 

 structure; tough, and usually clinking under the hammer, 

 like metal, when struck, whence the name. .Gr.=2 , 4-2*7. 

 Consists of glassy feldspar (orthoclase or oligoclase), with 

 nephelite and some hornblende. G. Jenzsch gives, for the 

 composition of the Bohemian phonolyte, Sanidin (glassy or- 

 thoclase) 53*55. nephelite 31-76, hornblende 9-34, sphene 3*67, 

 pyrite 0-0-4= 98 -36. Under treatment with acids the nephe- 

 lite is dissolved out. Kosean and hauynite occur in some 

 phonolyte. Eruptive only. 



4. HORNBLENDE AND POTASH-FELDSPAR SERIES. 



In this series the hornblende is sometimes replaced by 

 epidote, another anhydrous iron-bearing mineral, yielding 

 on analysis little or no alkali ; microcline is often present 

 as well as orthoclase. The species graduate into kinds con- 

 sisting almost solely of hornblende. Biotite is often pres- 

 ent as an accessory mineral. 



