268 IRVING. 



bles that from Maurice, except that the nephehnes are larger, 

 and more abundant. 



In the tinguaites automorphic nepheHne occurs less abund- 

 antly, and frequently cannot be detected at all. The presence 

 of nepheline, however, seems to be proved by the gelatinization 

 of the pulverized rock, as also by the analysis. 



In the trachytoid phonolites nepheline occurs only occasion- 

 ally in automorphic crystals, but gelatinization seems to indicate 

 that it occurs interstitially in the groundmass. A slide, when 

 treated with hydrochloric acid and stained with fuchsine, showed 

 irregular masses of gelatinized mineral, irregularly placed among 

 the feldspars. 



Nosean. — This occurs in great abundance in the phonoHtes 

 proper and to a slightly lesser degree in the tinguaites. It 

 seems to accompany the nepheline to a large extent, being 

 present in the greatest abundance in those rocks containing the 

 most of that mineral. It occurs in large dusty hexagonal sec- 

 tions mostly showing a clear border. Sometimes several crys- 

 tals will be grouped together in parallel growth. It antedates 

 the feldspar phenocrysts in the age of its formation. It con- 

 tains inclusions of aegirine in great numbers, but always 

 small and irregular. They seem to have a slightly green tinge, 

 and are identical with a mass of little kernels of the same mineral 

 grouped against the sides of the crystal, and apparently ex- 

 cluded from it during the process of crystallization. 



The nosean is always automorphic, and occurs as frequently 

 embedded in the phenocrysts of feldspar as in the groundmass. 

 It is often found partially included in the phenocrysts and 

 partially in the groundmass without. In the trachytoid phono- 

 lites, nosean is absent. 



Hailync. — This was found only in a single instance, and then 

 in very small although beautifully developed crystals. The 

 rock in which it occurs is an extremely fine grained variety of 

 phonolite, and was collected from a mass of irregular form, near 

 the mouth of one of the northeastwardly draining tributaries of 

 Squaw Creek. This Gulch is the second to the west of Lab- 

 rador Gulch. 



