S. Stanley Jerons — Nomenclature of Igneous Rocks. 313 

 Pamily III.— MIDALKALITES. (=NepheHne- orEl^oHte-syenites.) 



Two Index Minerals : An alkali-felspar ; and nepheline. 

 SiO, % 60-48. 



1. Pyr-midalkalite (= Foyaite, Blum ; Pvroxene-foyaite, 



Ros.). 



2. Amphi-midalkalite (= Ainpbibole-foyaite, Ros.)- 



3. Bi-midalkalite (= Mica-foyaite, Ros. ; incZwdes Miascite ; 



and Ditroite). 



4. Natro-midalkalite (= Litchfieldite). 



5. Rhomfels-pyr-midalkalite (= Laurdalite). 



6. Eudasgi-midalkalite (= Lujaurite). 



7. Leuci - midalkalite (includes Leiicite- syenite of Magnet 



Cove, Arlcansas). 



8. Cancri-midalkalite (= Cancrinite-syenite). 



9. Melano-midalkalite {includes Borolanite ; and nepheline- 



syenites of Montreal and Magnet 

 Cove, Ark. [Cove-type]). 

 10. Sodali-midalkalite {includes Sodalite-syenite of Juliane- 



haab). 

 Family IV.— ESSEXITES. 



Three Index Minerals : Labradorite ; augite or diopside ; 



and biotite {or an alkaline amphibole or pyroxene). 

 Si O2 % 50-43. 



1. Multifels - essexite {includes Essexites of Caho Frio ; 



Jacupiranguinha; BongstocTc; and 

 Dignaes). 



2. Mediofels-essexite {includes Essexites of Salem, Mass. ; 



and Solvsberg). 



3. Paucifels - essexite {includes Essexites of Arkansas ; 



Montreal ; Penikhavaara, near 

 Kuusamo ; and Brandberg). 



Family V.— THERALITES. (= Theralites and Shonkinites.) 



Three Index Minerals : A pyroxene ; felspar (plagioclase 



or orthoclase) ; and nepheline, or sodalite, or leucite. 

 Si 0, % 50-40. 



Subfamily A.— NATROTHERALITES. 



1. Augi-natrotheralite ' (= Theralite, sen. str. ; and includes 



most of the Tescbenites). 



2. ^gi-natrotberalite (= Natronsussexite). 



3. Barke-natrotberalite (= certain Tescbenites). 



Subfamily B.— KALITHERALITES. 



1. Augi-kalitberalite ^ (= Sbonkinite). 



2. jEgaugi-kalitberalite (= Pyroxene-malignite). 



3. Ampbi-kalitberalite (= Ampliibole-malignite). 



4. Melano-kalitberalite (= Garnet-malignite). 



1 The a of natro- and of kali- is pronounced long as in ' state.' The / of kali- is 

 short as in ' pit,' but it is dropped in the name kalijolite, in which the first i should 

 be pronounced long as in ' write.' 



