418 THE JOURNAL OF GEOLOGY. 
by the writer that the jasper is not metamorphic, but that it is 
formed to a considerable extent of the remains of siliceous organ- 
isms of the radiolarian type. This opinion was based on the 
study of a number of thin sections of the rock from widely sep- 
arated portions of the Coast Ranges. F. Leslie Ransome has 
recently announced the discovery of the first radiolarian remains 
found in a state sufficiently well preserved for description. Many 
specimens of jasper were collected on the recent trip through 
Monterey and San Louis Obispo counties, and nearly all showed 
the radiolaria visible to the unaided eye. The best were obtained 
from a large outcrop of greenish white jasper on the Eagle Rawehe 
six miles northwest of Santa Margarita. A microscopic study 
shows that portions of this rock are made up almost wholly of radi- 
olaria which are in a better state of preservation than any previously 
found, fifteen or more specific forms being made out. The jasper 
beds vary from a few feet to more than a hundred feet in thick- 
ness, and exhibit more or less distinctly a banded structure. 
The bands are often contorted so as to present a beautiful wavy 
appearance. The accompanying illustration is from a photo- 
graph of a magnificent outcrop on the coast of Monterey near 
the mouth of the Sur River. It illustrates both the banding and 
the wavy structure. Comparatively uniform conditions must 
have existed over the whole of the area covered by the Golden 
Gate series, where the rocks were being deposited, for the jasper 
beds are found almost everywhere that the rocks of this series 
are exposed. Similar conditions did not obtain during the Cre- 
taceous, for jasper is not known in any beds of that age on the 
Pacific coast. The series of beds of which the jasper forms such 
a striking feature undoubtedly possess a great thickness, but they 
have not yet been studied sufficiently in regions where the great- 
est development occurs to admit of any definite statement of 
their thickness. It is not probable that the jasper is confined to ~ 
one horizon in the series, and the strata have been so sharply 
folded, shattered, and crushed together by orographic move- 
ments, as well as by the intrusion of numerous eruptives, that its 
study is accompanied by uncommon difficulties. Sandstone 
