ACADEMY OF SCIENCES. 297 



out horizontally in the face of the bluff a few feet only above the level of the 

 beach, ami buried beneath thirty to fifty of half consolidated sand and fine 

 gravel forming- the upper part of the bluff. Eighteen or twenty years since 

 this stum]) was half covered up by the foot of the bluff, which is now fully twenty 

 feet from the stump. At this point, when the tide is very low, the tops of 

 other stumps may be seen standing upright, about a hundred yards outside the 

 present low water line. Another indication of oscillation is shown in the ex- 

 istence of a remunerative bed (if similar auriferous black sand, two or three 

 miles inland, and about one hundred and ninety feet above the sea. In o{)euing 

 a tail-race from this deposit to the sea, the cut exhibits a section from twenty- 

 five to forty feet deep, marked by horizontal alternating layers of sand, fine 

 gravel and a few thin layers of soil ; sticks and logs are not uncommon in the 

 mass, and some trees were unearthed still standing where they grew ; he exam- 

 ined two or three stumps of trees yet upright and forty feet below the present 

 surface. These stumps had the same carbonized appearance as the stump on 

 the beach. Part of the forces required to effect these changes was doubtless 

 wind, and other indications pointed to running water as an agent. 



From the mouth of the small creek five miles north of the Coquille, a bluish 

 gray, rather soft sandstone makes its appearance, underlying, and proljably uu- 

 conforraably, the more recent bed he has described. As it stretches northward 

 it increased in elevation, and forms several rocky islets off the shore line. 



At the " black sand " deposit, existing two or three miles inland, the stratum 

 is from two to nine feet thick and overlaid by thirty to fifty feet of reddish 

 sand. In a second mine in the same vicinity the '-islack sand" averages five or 

 six feet thick. With the gold is found some platinum, mingled with more or 

 less iridosraine, and occasionally pellets of native copper, bright and malleable, 

 are fouud. The difficulty of saving all the gold in this deposit consists in its 

 extreme fineness, and also in its being watered with a film which protects it from 

 the action of mercury. It is not clear what this film is, but by washing tlie 

 black sand for several hours and then working it in an arastra, two or three 

 times more gold is recovered than without washing. Plattner's process by 

 chloriuation was to be tried at one of the mines. 



From Roseburg to the head of the Willamette Valley, Mr. Goodyear no- 

 ticed much unaltered rock, shells and sandstones, in the railroad cuts. At Al- 

 bany, he first noticed volcanic pebbles in the gravel used in ballasting the road. 

 Twenty-five miles before reaching Portland, the basaltic bluffs were met on the 

 right bank of the Willamette, and thence continued throughout the region he 

 traversed as far as the Dalles of the Columbia river. He called attention to a 

 striking contrast between the character of the volcanic matter of this region 

 and that of the western slope of the Sierra Nevada, in California. The Cas- 

 cade Mountains, where the Columbia cuts through them, appear to be made 

 up entirely of a series of superimposed sheets of lava, which, when it flowed, 

 ran not in narrow streams, but spread far and wide over the then smooth and 

 gently sloping lands. They therefore consist of terraces of solid, compact rock 

 from base to summit, and the quantity of breccias is very small. On the con- 

 trary, the western slope of the Sierra Nevada shows its volcanic matter almost 



