506 



/. H. O GIL VIE 



ANALYSES. 



II. 



III. 



IV. 



VI. 



SiO, 



A1 2 3 



Fe 2 O 



FeO 



CaO 



MgO 



Ti0 2 



MnO 



K 2 



Na 2 



Loss on ignition. 



H 2 



co 2 



p 3 o 5 . 



Total 



38-45 



19.68 



4.01 



II. 15 



9-37 



6.65 



trace 

 1 .72 

 2.77 



1.49 

 4.82 



IOI.65 



IOO.44 



99.64 



100.07 



99.22 



I. The Las Vegas rock. 



II. Camptonite from Campton Falls, N. H. Published in Bull. 148, U. S. GeoL 

 Survey, p. 67. 



III. Camptonite from Campton Falls, N. H. J. W. Hawes, Am. Jour. Sci. 

 Ser. 3, Vol XVII, p. 150. 



IV. Gabbro from Rosswein, Saxony. Landwirthsch Versuchs station 40, 1892. 



V. Diorite from Lindenfels, Hesse Darmstadt. Chelies & Klemm, Erlauterung 

 zur Geologischexi Karte von Hesse, 1896. 



VI. Basalt, middle flow, Carlsbad, Bohemia. Jahrbuch der Koniglich Kaiser- 

 lichen Gesellschaft Kunstaustellnng, Vol. XL, p. 345, 1890. 



blende as the principal ferro-magnesian mineral ; augite camp- 

 tonite is applied to those in which augite equals or exceeds 

 hornblende ; analcitite to those containing primary analcite. 

 Rosenbusch's latest definition (1901) includes augite as an 

 essential constituent of a camptonite, thereby departing from 

 the original type of Hawes in which hornblende predominated. 

 In the case of the Las Vegas rock hornblende and augite 

 occur in approximately equal quantities. Since the tests for 

 analcite were not conclusive, the rock could not be called an 

 analcitite. It seems most logical to regard equal amounts of 

 hornblende and of augite as distinctive of a camptonite, restrict- 

 ing augite camptonite to those with augite in excess. The Las 

 Vegas rock can thus most logically be termed an analcite bear- 



