170 PROCEEDINGS OF THE ACADEMY OF [Part I 



site) from a large boulder of white saccharoidal albite which was 

 found in the bed of a stream at the foot of the Sierras near Berkeley. 

 The boulder contained also veins of actinolite. 



France: In 1900, Lacroix noted the occurrence of albitite dikes 

 in the peridotites of Bellongue (Ariege), France, consisting essenti- 

 ally of albite-oligoclase.'^ 



Ural Mountains: Duparc and Pamfil have described albitite 

 from Koswinsky, in the northern Ural Mountains, where it forms 

 aplitic dikes in dunite. ^ As in the case of the California and French 

 occurrences no data was given as to the relation of the albitite to 

 the country rock, beyond the fact that it formed intrusives in ser- 

 pentine or peridotite. 



The Russian albitite is associated with a series of related rocks 

 which have been named granulite, gladkaite and plagiaplite. 



The granulite is a rock composed essentially of quartz, andesine, 

 and biotite, forming veins in the dunite of Koswinsky. 



Gladkaite is a fine grained aplite composed of oligoclase and an- 

 desine, with much quartz, some hornblende and biotite, and secon- 

 dary muscovite and epidote. It forms dikes in the dunite at Glad- 

 kai Sopka, and Kamenouchky. 



Plagiaplite is an equigranular aphte composed of oligoclase or 

 andesine, with variable amounts of quartz and hornblende, and 

 subordinate muscovite or biotite. This rock forms dikes in the 

 pyroxenites of Koswinsky and Kamenouchky. 



This series may represent granitic pegmatites which differ in the 

 degree of desilication which they have undergone. Analyses of 

 them are given by Duparc and Pamfil. 



The occurrence of albitic dikes in the serpentines of New South 

 Wales was noted by Benson^ who considered them as being geneti- 

 cally related to the peridotites. 



Plumasite. 



California: The name plumasite was given by Lawson to an 

 oligoclase-corundum rock forming a fifteen foot dike in a serpentin- 

 ized peridotite on the lower flank of Spanish Peak, Bidwell Bar 

 quadrangle, Plumas County, California.* 



^ Alfred Lacroix, Comptes Rendus du VIII Congres International de Geologic 

 1900: 806-838, Paris, 1901. 



6 Bull. Soc. Franc. Min., 3.3: 347-375, 1910. 



'Proe. Linn. Soc. New South Wales, 38: 691, 1913; Am. J. Sci., (4) 46: 715, 

 1918. 



