24 GEOLOGICAL SURVEY OF TPIE TERRITORIES. 



tar below tlic toll-gate. The Port Neuf River is full of little falls or 

 rapids 3 toG feetliigli, where the water flows over the basaltic floor, add- 

 ing imieh to the attractive beauty of the scenery. Here and there we 

 lind outcroi)i)ings ot'cherty aud silicious limestones underlaid by shales.- 

 Isoliited hills prridges composed of these rocks are revealed by the river, 

 sometimes extending partly across the valley, remnants left from former 

 erosions. At the beud of Port Neuf a pretty little stream about 10 feet 

 wide flows in from the northeast. On the west side the rusty-gray 

 quartzites are well shown, inclining oij'^. In passing down the Port Neuf 

 from the bend, we have the yellowish-gray quartzites just mentioned, 

 then dull purplish quartzite, composed largely of an aggregate of quartz 

 pebbles, then dark i)urplish drab slates. The latter seem to form the cen- 

 tral portion of a local anticlinal. The reverse dip extends only a short 

 distance, while the original dip, a little north of east, is restored, and 

 this continues for five or six miles, the strata consisting of alternate beds 

 of quartzites, slates, limestones, &c., inclining 15^ to SU^. In this series 

 are three beds of impure cherty limestones. The quartzites possess a 

 great variety of texture aud color, from a dirty, rusty brown or rusty yel- 

 low to a fine grayish quartz. The reddish or purplish quartzite is very 

 thick, and forms most beautiful pudding-stones, very seldom a coarse 

 conglomerate. At the lower end of Port Keuf Canon, j ust before it opens 

 into the plain, there is a high ridge, rishig 1,500 to 2,000 feet above the 

 river, which seems to form the central mass of the general anticlinal, for 

 the strata dip each way from it. This ridge, as it extends off far south- 

 ward, shows the slopes or inclinations of the beds well. The Port Neuf, 

 after making the bend near Eobber's Roost City, cuts a channel through 

 the ridges nearly at right angles for five or six miles, exposing at least 

 10,000 feet of quartzite. The ridges run quite regularly north and south, 

 and the ijrincipal ones are very persistent, while connected with them 

 are some fragmentary ones. The age of this vast series of stratified 

 rocks is quite obscure, and may continue so. The limestones which con- 

 tain the well-defined Carboniferous fossils mark a horizon which takes in 

 a considerable thickness, but below this horizon there is a group of 

 strata of variable thickness, as v»^ell as texture, that is not likely to reveal 

 the i)roois of its age. It is true that there is ample room for several times 

 as great a thickness of strata in the Devonian and Silurian, and even 

 extending down into the sub-Silurian, where, perhaps, soine of the meta- 

 morphic quartzites should be placed. In this report I shall merely state 

 the facts as I have been able to observe them, and await the results of 

 future explorations to clear up any obscurities. In this great country the 

 formations are usually so widely extended geographically that the discov- 

 ery of proofs of their age at any one locality may unravel the obscurities 

 of years of labor. Limestones of undoubted Carboniferous age occur every- 

 where, and, as a rule, cover the summits and flanks of the highest ranges 

 of hills or mountains. In many instances the great thickness of these 

 limestones and the slowness with which they yield to atmospheric in- 

 fluences have prevented many of the ranges from being much rounded, 

 and perhaps removed entirely. Over a great portion of Utah, extending 

 northward into Idaho and Montana, the Carboniferous limestones form the 

 great protecting covering to the mountain ranges. The erosion of the 

 basalt in the Port Neuf Canon is a feature of some interest. Sometimes 

 for miles it has been entirely removed ; then it will re-appear in full force. 

 Remnants are sometimes seen on the sides of the caiion, showing that the 

 waters at a modern period have worn wide channels through. In some 

 instances there are evidences of two great periods of outflow of melted 

 material, forming horizontal belts, as it were. At one locality this fea- 



