202 GEOLOGICAL SURVEY OF THE TEREITOEIES. 



The next range east was also examined in a hasty reconnaissance up 

 New Canon, wliieli opens into the valley about four miles east of Kee- 

 ney's Station. The lower portion of the caiion is walled with heavy 

 beds of ferruginous quartzite, belonging with the lower beds at Ogden, 

 and, like tliem, referred with little doubt to the Potsdam. Some small 

 excaTations have been made by mining prospectors in some of the more 

 thinly-bedded portions, but without any success. Their rubbish gave 

 no indication of anything which should have encouraged such excava- 

 tions. Above the quartzite lie heavy- bed died, darli-blue and ferruginous, 

 impure limestones, which belong to the Quebec group ; but no fossils 

 were found. Tiie dips are all easterly and reach 50°. The upper part 

 of the caiion is heavily timbered with pine and spruce; and residents 

 of Malade City have combined to make a good wagon-road up it, for 

 the purpose of more readily obtaining a supply of timber for building 

 purposes and for fuel. The sharp dips of the caiiou are much flattened, 

 a little farther south, so that in the course of a few miles the quartzite 

 and the lower i^ortiou of the limestone disappear beneath the upper 

 edge of the abutting Tertiaries of the valley. A caiion on the east side 

 of the mountain north of Keeney's Station has yielded a considerable 

 amount of maple-timber, a foot or more through at the butt, and oO to 

 40 feet long. 



The small stream-valley which the stage-road follows runs over to the 

 east side of the main valley between the ridges, and leaves the Terti- 

 aries exposed in white banks upon the slopes of the western ridge. Mr. 

 Stevenson reported having examined these for fossils without success. 



About eight miles from Malade City, we reached the divide between 

 the waters of the Great Basin and those of the Columbia. The upper 

 lake-terrace, which has been a marked feature of the country thus far 

 upon our journey, with small exceptions, here becomes a little irregular 

 and much washed, but apparently reaches to the very summit, as if this 

 might have been a point of dribbling outflow for the waters of the great 

 lake when at its highest level. This is also true of the point in the 

 upper course of Bear Eiver, where the Port Neuf most nearly ap- 

 proaches that stream in the same broad valley, with only remnants of 

 the old terraces forming the divide between them. The level of the 

 divide between the head of Marsh Creek and the Bear Eiver drainage, 

 at Eed Eock Pass, as ascertained by the party of 1S71, indicates that 

 this was probably another point of outflow ; and the divide between the 

 head of the Malade and Bannock Creek may very probably have been a 

 fourth, since Captain Mullan reports that as " prairie-surface of clear 

 gravel formation." (See Wagon-road Eeport, 18G3, p. 70.) Time for- 

 bade our working out the details of these points by the way, and I can, 

 therefore, only offer these suggestions as to points worthy of more de- 

 liberate examination. Without any very accurate determinations of 

 levels, I am yet inclined to believe that the terrace-levels rise somewhat 

 as we pass to this northern rim of the basin, implying a moderate up- 

 heaval of the whole country in that region, which may have taken 

 place while the lake was yet full, and so have been the first means of 

 separating the Great Basin from the Columbia drainage. I agree, how- 

 ever, with those who hold that the decline of the lake from these old 

 terrace-levels has been due mainly toaclimatal change, which decreased 

 precipitation, but either left the cvapcu'ation constant or increased it. 

 These variations in the lake-level are still going on, as is shown in the 

 recoi'ded rise of the surface for about twelve years, until, two years ago, 

 it began to decline again. I have questioned, in my own mind, 

 whether this latter decliue does not really represent the result of dimin- 



