Fairbanks.] 



Geology of Point Sal. 



19 



farther north in the Coast Ranges. There is a predominance of 

 the same dark, soft shales, with a subordinate amount of thin-bedded 

 sandstone. As a general thing the beds lie nearly flat, although in 

 places they have been considerably disturbed. When tilted, they 

 strike east and west, with a predominating dip to the north. A num- 

 ber of poorly preserved specimens of Aucella piocliii, Gabb, were 

 found in the shale. The smaller outcrop down the valley contains 

 more sandstone with some conglomerate, and has an apparently 

 horizontal bedding. The Aucella was found here in the sandstone. 



Relation to the Spheroidal Basalt. — The relation existing between 

 the Knoxville and the spheroidal basalt was not satisfactorily 

 settled. A small laccolite like boss appears intrusive in the larger 

 Knoxville area, but it is a question whether it belongs to the same 

 eruptive body so prominent west of the Knoxville. The small 

 eruptive mass within the latter has considerably metamorphosed 

 the shales, but the large body of basalt and related rocks to the 

 west has, as far as could be detected, no effect upon them. A 

 small outcrop of conglomerate was seen not far from the basalt, 

 and a similar conglomerate was quite prominent at the small out- 

 crop down the valley. As the high basaltic ridge rises between 

 these two outcrops, it is possible the conglomerate might indicate 

 a shore line, although no fragments of the basalt could be found. 

 However, the presence of similar occurrences of spheroidal basalt 

 in the older uncrystalline rocks of the Coast Ranges, and the 

 entire lack of disturbance and metamorphism in the adjoining 

 shales, makes it seem highly probable that the basalt antedates the 

 Knoxville. 



AUGITE-TESCHENITE. 



Occurrence. — The type of eruptive rock to which the term 

 augite-teschenite is given, is identical with that previously described 

 by the author under the name Analcite Diabase.* The dikes of 

 this rock are confined to the southern slope of the ridge east of the 

 Old Landing. The slope is so abrupt here that, owing to the soft 

 nature of the Miocene clays, and the disintegrated condition of 

 the teschenite, slides are constantly occurring, and the exact loca- 



*Bull. Dept. Geol. Univ. Cal., Vol. I, p. 273. 



