No. 1. 
REPORT UPON THE GEOLOGY OE THE ROUTE. 
BY J. S. NEWBERRY, M.D. 
GEOLOGIST OF THE EXPEDITION. 
CHAPTER I. 
GEOLOGY OF THE VICINITY OF SAN FRANCISCO. 
General features given by parallel axes of elevation.—Bay of san francisco occupying a synclinal trough.—General 
TREND OF RANGES NORTHWEST AND SOUTHEAST.—COAST MOUNTAINS GIVE OUTLINE AND DIRECTION TO THE COAST.—LOCAL 
geology.—San francisco range.—Golden gate cut through it.—Centre, trap and serpentine.—Physical characters of 
THE SERPENTINE.— CHEMICAL ANALYSIS.—SERPENTINE, SANDSTONES, AND SHALES.—PlTNESS OF THE SANDSTONE FOR ARCHITECTURAL 
PURPOSES.— IT CONTAINS FEW FOSSILS.—ScUTELLA INTERLINEATA.—JASPER.—DRIFTING SAND.—ALLUVIAL DEPOSITS.—GEOLOGY OF 
SAN PABLO BAY.—SANDSTONES AND SHALES OF THE SAN FRANCISCO GROUP.—SANDSTONES FOSSILIFEROUS.—PECTEN BED.—OTHER 
FOSSIL SHELLS.—TUFAS AND MARLS FORMING SERIES OF GREAT THICKNESS.—UPPER MEMBERS VERY MODERN, AND OF VOLCANIC 
origin.—Beds of recent oyster shells.—Changes of level.—Probable communication formerly existing between san 
PABLO BAY AND THE OCEAN.— Sl'RAITS OF CARQUINES—SANDSTONES AND SHALES.—LaMINjE OF GYPSUM.—BeNICIA.—SANDSTONES 
EQUIVALENTS OF THOSE OF SAN FRANCISCO.—BlDGE OF JASPER NORTHWEST OF BENICIA.-WARM SULPHUR SPRING.—SOIL.—GEOLOGY 
OF MOUNT DIABLO.—GOLD.—SUISUN BAY.—CALCAREOUS TUFA.—TRAP HILLS.—SAN FRANCISCO SANDSTONE FORMING HILLS NEAR 
Vacaville. 
GENERAL FEATURES. 
The configuration of the country in the vicinity of San Francisco has been given by two prin¬ 
cipal, and nearly parallel lines of upheaval, one passing between the city and the Pacific, 
forming the harrier through which the Golden Gate has been cut, the other that of the Contra 
Costa mountains. These, with several subordinate axes, which exert a local influence on its 
structure, properly belong to the compound chain of the coast mountains, have the same geo¬ 
logical structure, and are doubtless of the same age. They are composed of serpentine or trap 
at centre, flanked by heavy beds of shales and sandstones of the tertiary period. 
The general trend of these ranges is northwest and southeast, and they belong to the same 
system of elevation with that which has given the general outline and direction of the coast 
from Cape St. Lucas to Cape Mendocino. The islands which are scattered along the coast of 
California within the limits specified apparently lie in the lines of some of the axes of this 
system. 
The Bay of San Francisco and the valley south of it occupy the synclinal trough which lies 
between the two axes I have mentioned. This depression, geologically considered, forms but a 
single area, which should he viewed as a whole, and which may properly he termed the valley 
of San Francisco hay. Of this area the valley of San Juan forms the southern, San Francisco 
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