6 
CONTENTS. 
CHAPTER IV. 
Geology of Pit River and Klamath basins. 
Pit River basins.—Lake-like character of the lower basin.-—Proofs that it has once been a lake.—Infusorial sediments 
deposited by its waters.—Range forming the upper canon of Pit river.—Second basin of Pit river.—Infusorial marls.— 
Hills of metamorphic slate, greenstone, porphyry, and trap bordering Pit river.—Geology of the country about the head of 
Pit river.—Hot springs and infusorial marls.—Klamath basins typical illustrations of the geological structure of a large 
area.—Common features of the region lying east of the Sierra Nevada and the Cascades.—Not one but many basins.—- 
Klamath basins once lakes.—Local geology.—Fit river to Wright lake—Recent volcanic cone.-—Cliffs bordering Rhett lake 
of sandstone and trap.—Efflorescence on the shores of Rhett lake.—The Natural Bridge a fault.—Infusorial marls of Lost 
river and lower Klamath lake.—Metamorphic form of these marls, resembling jasper.-—Geology of the shores of Klamath 
lake.—Basaltic conglomerate on Klamath river.—Infusorial marls.—Pumice.-—Trap ranges south and east of Klamath 
marsh.—Pumice plain between Klamath marsh and the Des Chutes river. 
CHAPTER Y. 
Geology of the Cascade mountains. 
Panoramic view of the Cascade mountains.—Sierra Nevada and Cascade mountains.—A wall crowning the western 
margin of the great central plateau.—Structure and origin of the Cascade range.—Main crest near its eastern margin, a line 
of volcanic peaks.—More westerly mountains, metamorphic slates.—Local geology.—Crater Pass.—Evidences of glacial 
action.—Glaciers once descended far below the present snow line--—Extent of glaciers in the Cascades.—Conditions under 
which they must have been formed.—By elevation or change of climate ?—Evidences of elevation.—Sub-aerial excavation 
of mouths of rivers.—-Depression of temperature would produce greater precipitation of moisture.—Streams flowing from 
the Cascade mountains formerly larger than now.—Canons of those streams not rifts but excavations. 
CHAPTER VI. 
Geology of the Des Chutes basin. 
Compound nature of this basin.—Its subdivisions similar in structure to those of Pit and Klamath rivers.—Trap 
plateaus.-—Volcanic tufas and infusorial marls.—Local geology.—Plateau east of the Three Sisters.—Canon of Mpto-ly-as 
river.—Mount Jefferson.—Congealed lava stream.—Castle Rock.—Columns of basaltic conglomerate capped with blocks of 
trap.—Tufaceous strata of Mpto-ly-as river.—Canon of Psuc-see-que creek.—Picturesque appearance of the colored tufas 
and concrete.—Trunks of coniferous trees imbedded in tufa.-—Columnar trap covering the tufas.—Warn Chuck river.— 
Hot springs.—Gelatinous silica.—Metamorphosed tufas.—Onyx, opal, agate, silicified wood.—Warn Chuck mountains.— 
Metamorphic slates.— Quartz and chalcedony.—Nee-nee springs.—Metamorphosed marls.-—Ribband jasper.—Plateau of 
Tysch prairie.—Tysch mountains.—View of Mount Hood.—Canon of Des Chutes river.—Mounds.—Hills of infusorial marl 
south of the Columbia. 
CHAPTER VII. 
Geology of the country bordering the Columbia river. 
Region east of the Cascade mountains.—General features apparently similar to those of Des Chutes basin.—Local 
geology.—Dalles of the Columbia.—Sedimentary infusorial deposits.-—Their fresh water origin.-—Their age.—The canon of 
the Columbia.—General features.—How formed.—Local geology.—Horizontal strata of trap.—Submerged forest.—Cascades 
formed by slide from mountains.—Conglomerate.—Silicified wood.—Tertiary strata below Cascades.—Country bordering 
the lower Columbia.—General features.—Willamette valley.—Local geology.—Western slope of the Cascade range.—Canon 
of McKenzie’s fork.-—Marks of glacial action on Mount Hood.—Trap, scoria, ashes, &c., from Mount Hood.—Trap and 
sandstones of Willamette valley.—Erosion of sandstones.—Lignites near St. Helens.—Terraces.—Coast mountains.—Sand¬ 
stones and shales of Astoria.—Fossils.—Age of the deposit.—Port Orford.—Tertiary sandstones.—Trap.—Gold. 
