CHAPTER VIII. 
ECONOMICAL GEOLOGY. 
Building materials in the vicinity of san francisco.—San Francisco sandstone.—Granite from hong kong.— Of tomales 
bay.—Limestone of tomalps bay.—Sandstones of benicia.—Sandstone and trap of Vacaville.—Want of building 
STONE ON THE SACRAMENTO AND FEATHER RIVERS.-TRAP NEAR UPPER END OF THE VALLEY.—-FROM FORT READING TO THE 
COLUMBIA, TRAP EVERYWHERE ON OUR ROUTE. •—GOLD.- No NEW DEPOSITS DISCOVERED.-COUNTRY COVERED BY RECENT 
VOLCANIC MATTER.- — GOLD OF PORT ORFORD. COAL.—EFFORTS TO FIND TRUE COAL ON THE WESTERN COAST. COOSE BAY 
COAL ; GEOLOGICAL POSITION ; PHYSICAL AND CHEMICAL CHARACTERS ; ECONOMICAL VALUE.-COAL OF BELLINGHAM BAY; 
GEOLOGICAL POSITION; EXTENT AND THICKNESS OF THE BEDS; ASSOCIATED FOSSILS.-MlOCENE FLORA.-LlGNITE BEDS OF THE 
upper Missouri.—Chemical and physical character of bellingiiam bay coal.—Its economical value.—coal of van- 
• couver’s island; geological position.—Cretaceous rocks.—Parallelism of the chalk and tertiary of the upper 
MISSOURI AVITH SIMILAR STRATA ON THE PACIFIC COAST.-PHYSICAL CHARACTER OF THE COAL AND ITS CHEMICAL COMPOSI¬ 
TION.—Coal of cape flattery, probably the equivalent of the lignites of the coavlitz and coose bay.—Coal of 
SANTA CLARA, CALIFORNIA.-COAL MARKET OF SAN FRANCISCO.—COAL OF THE LOTA MINE, CHILI.-COAL OF AUSTRALIA.- 
Coal from the eastern states. 
BUILDING MATERIALS. 
VICINITY OF SAN FRANCISCO. 
The only desirable building stone in the vicinity of San Francisco is the sandstone which 
is fully described in the first chapter of the report, where its fitness for architectural pur¬ 
poses is alluded to. It is very accessible, readily quarried and wrought, and will supply a 
cheap building material in exhaustless quantities. Some varieties of this stone, especially 
that quarried on Yerba Buena island, will even answer the demands of ornamental architec¬ 
ture, being to a considerable degree handsome and durable. For more elaborate and expensive 
structures, however, a more resistant as well as beautiful material will he sought; something 
which should fill the place of the granites, marbles, and finer freestones used in the eastern 
cities. Granite is already used to some extent in San Francisco, and it is now, for the most 
part, imported from Hong Kong, in China. In that part of California which we visited it 
was observed in hut one or two localities. From Tomales hay I obtained specimens of granite 
which seems well adapted to architectural purposes. It is composed of small crystals of white 
felspar and quartz, with minute scales of black mica, and forms a very compact and durable 
as well as handsome stone. There is also, on Tomales hay, a light-colored crystalline limestone, 
which, when obtained in blocks of sufficient size, will make an excellent building stone. It is quite 
extensively used for making quicklime. I have also seen specimens of metamorphic limestone, 
obtained in various parts of the Sierra Nevada, which, for beauty and durability, will almost 
rival the white marble of Vermont or the Potomac. The sandstones which are quarried in the 
vicinity of Benicia are similar in character to those of San Francisco, hut are softer and less 
desirable for architectural purposes than some found in the immediate vicinity of the city. 
From Benicia to Vacaville, the San Francisco sandstone is accessible at many points, and the hills 
which border the upper end of Suisun hay and Suisun valley on the west are composed of com¬ 
pact trap, which will afford a resistant and durable building material, hut one wrought with 
