GEOLOGY. 255 



quartzite, bUifFs of yellow gravel, blue talcose slate, conglomer- 

 ate, hard blue slates, and quartzose rocks, blue sandstones, and a 

 soft green rock (Plutonic) with light stellate spots in it. Granite 

 is very rare, and niica also. 1 have found 5 specimens of obsidian 

 on the beach, and just above the Ramparts, pebbles of Niagara 

 limestone with its characteristic fossils. From t!ie bend we find 

 the following strata: blue sandstone (unfossiliferous), brown 

 sandstone in beds at least 500 feet thick, containing vegetable re- 

 mains in some layers, and rarely casts of moUusca, all, as far as I 

 have collected, lamellibranchs. Thirty miles below the bend is a 

 small contorted seam of coal between 2 thin layers of siiale, con- 

 taining very poor vegetable remains, and underlaid by the brown 

 sandstone, which also overlies the blue sandstone, which in its turn 

 I think covers the blue slates. The coal seam is very limited, be- 

 ing on the extreme point of a bluff, and the greater part of it has 

 been denuded. The fossils are very poor, vegetable, and resemble 

 fuci. The coal is of good quality, bituminous, non-caking, and 

 leaves a gray ash ; the seam is 16 inches wide. 



"The sandstones continue down the river some 45 miles, more 

 generally with a north-westerly dip, and always in gentle undula- 

 tion, sometimes continuous for miles, and often broken short oif. 

 Below, the rocks for 300 miles are slates and eruptive rocks of a 

 pink color, sometimes containing spathose minerals. The formation 

 changes at the Russian mission from hard blue slate to a volcanic 

 rock, full of empty almond-shaped cavities ; but certain parts of 

 the rock are quite solid ; it is black, and contains minute crystals 

 of olivine (?). It is roughly columnar on Stuart's Island, Norton 

 Sound, in live-sided columns on the beach. From this to the sea, 

 the bajj^ks are mostly low, but when they approach the river they 

 are invariably blue, hard, slaty sandstone, or sandy slate, the rock 

 passing from one into the other imperceptibly. This forliiation 

 extends to St. Michaels, nearly where the above-mentioned vol- 

 canic rock takes its place, and continues up the shore of Norton 

 Sound some 30 miles, when it is replaced by the hard slates and 

 sandstone, and I have followed them up for 30 miles more to Una- 

 lakleet River. 



*' The entire country is sprinkled over with remains of pliocene 

 animals, Elephds, Ovibos moschatus, etc. (?). Beds of marl exist 

 near Fort Youkon, consisting of fresh-water shells still found living 

 in the vicinity. The Kotto River, emptying into the Youkon 

 above Fort Youkon, is.held in superstitious dread by the Indians, 

 on account of the immense number of fossil bones existins: there : 

 the Inglutalic River, emptying into the Norton Sound, has a some- 

 what similar reputation. 



"I have carefully examined the country over which I have 

 passed, for glacial indications, and have not found any effects at- 

 tributable to such agencies. My own opinion, from what I have 

 seen of the west coast, though yet unproved, is that the glacier 

 field never extended, in these regions, to the westward of the 

 Rocky Mountains, although small single glaciers have existed, 

 and still exist between the spurs of the mountains which approach 

 the coast. No boulders, such as are common in New England, 



