32 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



and fragments of most convenient shapes, cover the surface of the 

 country for miles around. 



Having- climbed the promontory, I observed that an old but quite 

 distinct trail passed along the brink of the ledge and descended the 

 broken cliiis to the valley above and below. In the vicinity of the 

 trail the glistening flakes proved to be more plentiful than elsewhere, and 

 were also apparently gathered into heaps. After a short search a 

 leaf-shaped implement of very fine workmanship was found; it is made 

 of the black opaque obsidian, and is 4 inches in length, 3 inches in 

 width and one-half inch in thickness; an outline of this implement is 

 given in Fig. 1, Plate XVI. Having continued the search as long as 

 the time at my command would permit, I was amply rewarded in the 

 possession of ten more or less perfect implements. Three are leaf- 

 shaped and nearly the same in size as the first specimen found, but 

 imperfect from having been broken. One is somewhat pyramidal in 

 shape, as shown in Fig. 2 ; the bottom is flat, the flaked surfaces extend- 

 ing from the base to the apex ; it is 2^ inches in width and If in height, 

 and is the only specimen in the collection that appears to have been 

 in the least used; the sharp edge at the base is considerably worn; Fig. 

 3 is a top view of the same. Another specimen is triangular in shape, 

 with sides about 3 inches long ; another is rectangular and about 3 

 inches wide by 4 in length, and still another is a rude oval; nearly al 

 of these implements are imperfect, as if broken or unfinished. If we 

 are to suppose that the great quantities of minute flakes are the frag- 

 ments left from the manufacture of implements, we must conclude that 

 extensive supplies have been obtained here, bat by what tribes or at 

 what period it will be quite impossible to determine. 



My observations in this region were too limited to enable me to deter- 

 mine the true relations of the obsidian rocks to the ordinary rhyolites 

 that surround them. Their horizontal extent is a matter of conjecture. 

 The western side of the valley rises in a steep, tree-covered s]oi)e to 

 an elevation of about 600 feet, the rocks exposed along the base being- 

 gray rhyolites. Above Obsidian Canon the valley expands somewhat, 

 and is occuj)ied by a shallow lake, about one mile in length by half a 

 mile in width at the widest part. It is intersected by a complicated 

 system of beaver dams. The water is strongly impregnated with alum 

 and other impurities and is quite unfit for use. About a mile above 

 the lake we cross the divide and enter the valley of Gibbon's Fork of 

 the Madison. The general character of the formations remains every- 

 where the same. 



In returning from the Gibbon Geyser Basin we turned up Indian 

 Creek on our way to the Gallatin Mountains. There are but few outcrops 

 of rock of any kind, and it is difScult to say just where the borders of 

 the rhyolites are. In preparing the geologic map I have colored a broad 

 belt along the west side of the Gardiner Valley as drift. 



WASHBURN KANGE. 



Of all the prominent mountain groups of the Park no one is so little 

 known as the Washburn Eange. Situated as it is in the midst of the 

 Park and between two of the great basins of the wonderland, it has all 

 along been simply an obstacle in the way of travel. It presents no feat- 

 ure of general interest, save the noble outlook obtainable from the chief 

 summits. Travel has always been by the one pass which leads across 

 the range near the west base of this peak. The several geologists who 

 have visited the Park confined their observations to the vicinity of the 



