34^ 



University of California. 



[Vol. i. 



has the new plutonic family of the monzonites come into existence 

 under the masterly treatment of Brdgger, and a great distress is 

 lifted from the diorites and syenites. It seems wiser to avoid the 

 confusion arising from such periodic evictions from the older fam- 

 ilies by freeing ourselves from the crude idea that the number of rock- 

 families must be limited to those we already recognize. A cramped 

 scheme of classification in the early stages of the development of a 

 science such as petrography is certainly a serious hindrance to the 

 progress of philosophic ideas. It is better to err rather on the side of 

 a somewhat diffuse classification at first, and to condense as relation- 

 ships become clearer and more settled. With these considerations in 

 mind the writer ventures to face a well-known and often-expressed 

 prejudice against the introduction of new rock names, and to pro- 

 pose the establishment of the new family of the Malignites to accom- 

 modate the new rock types described in the following pages. 

 These may be referred to as amphibole-malignite, garnet-pyroxene- 

 malignite, and neplicline-pyroxene-nialignite. In the petrographical 

 descriptions the last named will be considered first. 



NEPH ELI NE-PYROXENE-M A LIGNITE. 



Macroscopic Characters. — The rock is of a light gray color, 

 being composed of light and dark colored constituents in about 

 equal proportions, and presents the general aspect of a rather feld- 

 spathic dolerite of medium texture. The light-colored constituents 

 comprise: (i) Orthoclase in part fresh and glassy and in part milk 

 white; (2) a dead white mineral, nepheline, in a more or less 

 decomposed condition; and (3) glassy, bright greenish-yellow apa- 

 tite. The dark constituents are: ( 1 ) Lustrous black, elongated 

 prisms of pyroxene in great abundance; (2) occasional folia? of 

 brownish black biotite; and (3) somewhat rare grains of titanite. 

 When critically examined the hand specimens show by the uniform 

 reflection of the cleavages that the orthoclase is present in large 

 individuals, as much as 4 cm. in diameter, but the space occupied 

 by the feldspar is so charged with all the other constituents of the 

 rock that it does not otherwise appear prominent; and if it were 

 not for the cleavage reflections, there would be no suggestion of its 

 occurring in large individuals. In hand specimens it appears rather 



