42 



University of California. 



[Vol. i. 



are in addition a few scattered granules of magnetite. An analysis 

 was made of the rock, and although the total foots up too high, the 

 results are valuable and of interest. The analysis shows that the 

 rock contains 60 per cent, of silica, and it has a low specific gravity. 

 The abundance of glass, the high proportion of silica and water, 

 and the small amount of iron, serve to explain the great contrast in 

 the density of this facies with that of Sunium Point. The amount of 

 silica is greater than that usually found in the rocks classed as 

 basalts; chemically it falls in with the andesites. 



Analysis of carmeldite from the outcrop at the Carmclo lagoon. 



Specific gravity 2.51 to 



Si o 2 



60.00 



Al a 3 



19.01 



Fe 2 3 



3.20 



Fe'O 



0.68 



Mn O 



trace 



Ca 



4.10 



Mg 



1.28 



K, 



2.79 



Na 2 



6.97 



Ignition 



4-30 





102.33 



2-54- 





The Mission Area. — A low hill between the Carmelo Mission and 

 Mrs. Martin's farmhouse is occupied to the extent of a few acres by 

 a peculiar facies of the carmeloi'te. It has a prevailingly light pur- 

 plish blue color, and has a very distinct laminated appearance, due 

 to the banding of the rock with thin purplish brown layers. This 

 banding is not uniform in character. When it is best displayed the 

 brownish layers are about a millimeter thick, and are several milli- 

 meters apart. The rock tends to split parallel to the lamination. 

 Sometimes the banding is absent. Locally, also, the mass may 

 present a whitish bleached aspect. Phenocrysts of iddingsite are 

 usually abundant. Microscopically the ground-mass consists of a 

 feltwork of plagioclase and iddingsite, with scattered grains of mag- 

 netite and considerable interstitial glass. The purplish blue por- 

 tions of the rock are represented in the slide by areas rich in black 



