April 20, 1: 



SCIENCE 



185 



"been added to our up-stream journey that it would become 

 •doubtful whether we should be able to afford time for geological 

 ■work on the Lewes, and reach the coast before the smaller lakes 

 near the mountains were frozen over. I therefore decided to set 

 about the building of another boat, suitable for the ascent of the 

 Lewes, and on the second day after we had begun work Mr. Ogil-" 

 vie very opportunely appeared. After having completed our boat 

 and obtained Mr. Ogilvie's preliminary report and survey sheets, 

 together with the necessary provisions, we began the ascent of the 

 Lewes, from the head waters of which we crossed the mountains 

 by the Chilkoot Pass, and reached the coast at the head of Lynn 

 Canal on the 20th of September. I am happy to be able to add that 

 the entire expedition was carried out without any serious accident or 

 loss, notwithstanding the difficult nature of the country, and that, 

 though circumstantial reports were heard in the spring, of trouble 

 between the miners and Indians on the Yukon, these proved to be 

 entirely groundless." 



Mr. Ogtlvie proceeded down the Pelly River, and is now winter- 

 ing in the vicinity of Belle Isle. It was proposed to make astro- 

 nomical observations corresponding to those of Mr. Ogilvie near 

 the point of intersection of the Yukon and 141st meridian at two 

 places, — Kamloops and Ottawa. Unfortunately the correspond- 

 ing observations could not be carried out, and the value of Mr. 

 Ogilvie's astronomical work is therefore problematical. This spring 

 he will start for the mouth of the Mackenzie by way of the Porcu- 

 pine River and Fort Macpherson, and ascend the Mackenzie to 

 Port Chipewayan, connecting with his own survey of the Peace and 

 Athabasca Rivers. 



THE GEOLOGICAL OBSERVATIONS OF THE YUKON 

 EXPEDITION, 1887. 



The routes to be followed by the expedition were selected with 

 the purpose of obtaining as much information of a geographical, 

 geological, and general character as possible of the great tract of 

 country included in the extreme northern part of British Columbia, 

 and to the north of the 6oth parallel (which forms the boundary- 

 line of that province), between the Rocky Mountains proper on 

 the east, and the borders of Alaska on the west. The greater part 

 of this vast region is drained by several large tributaries of the Yu- 

 kon River, but these interlock to the south with tributaries of the 

 Stikine and with branches of the Liard, a feeder of the Mackenzie. 



The results obtained will form the subject of a detailed report of 

 the Geological Survey of Canada, but for the preparation of this 

 some time is yet required ; and Mr. Ogilvie of the Dominion Lands 

 Branch, and Mr. McConnell of the Geological Survey, are still in the 

 field for the purpose of continuing surveys and explorations next 

 summer. Meanwhile the following notes, bearing particularly on 

 the principal geological features of scientific importance, may prove 

 of interest. 



In 1879 a geological traverse was made by the writer, of the en- 

 tire width of the Cordillera region, by the line of the Skeena and 

 Peace Rivers {Report of Progress of the Geological Survey of Can- 

 .ada, 1879-80) ; but this had, so far, remained the most northern 

 line of geological examination across the wide mountain-belt of the 

 west coast of the continent. The work of the past summer in- 

 cluded a similar traverse of the same belt by the Stikine, Dease, 

 ■and Liard Rivers, at a minimum distance of two hundred miles 

 north of the last, and extended by the last-named river completely 

 through the Rocky Mountains, to the great valley of the Mackenzie. 

 The latter part of the traverse was, however, undertaken by Mr. 

 McConnell, and his observations are not yet available. 



To the north of this cross-section the exploration extended in the 

 Yukon basin to the mouth of the Lewes River, near the 63d parallel. 

 The actual line of travel and survey followed the Liard from its 

 junction with the Dease northward toils sources, crossed the height 

 of land to the Pelly near its head waters, followed that river down 

 to the mouth of the Lewes, ascended the Lewes southward to its 

 head, and finally, traversing the coast mountains by the Chilkoot 

 Pass, reached the head of Lynn Channel. 



The entire region thus examined may be described as mountain- 

 ous in general character, though comprising also wide areas of hilly 

 or rolling country, and many important flat-bottomed river-valleys. 



It declines as a whole gradually to the north-westward from heights 

 of 2,730 feet at the Stikine-Dease watershed, and 3,150 feet at the 

 height of land between the Liard and Pelly, to 1,550 feet at the con- 

 fluence of the Lewes and Pelly. The close-set mountains forming 

 the coast ranges on one hand, and on the other the serried peaks 

 at the base of which Frances, Finlayson, and Pelly Lakes lie, and 

 which represent the western tier of the Rocky Mountains, are here 

 the principal mountain axes. A third important intermediate 

 range, which it is proposed to name the Cassiar Range, is. 

 however, cut through by the Dease River immediately to the east 

 of Dease Lake. This appears to be continuous in a north-west- 

 ward direction to the Pelly, after reaching which it assumes a more 

 westward course, and with decreasing altitude follows parallel to 

 the river, which it eventually crosses, near the mouth of the Lewes, 

 in the form of low ranges of hills. The trend of the subsidiary and 

 less continuous ranges to the west of the Rocky Mountains proper, 

 as well as the prevailing strike of the rocks, partake in a similar 

 general change in direction, wheeling westward in the north in ap- 

 proximate conformity with the outline of the Pacific coast. 



The rocks throughout the entire region above outlined present 

 close analogies to those already investigated in the southern portions 

 of British Columbia, thus confirming previous statements with re- 

 spect to the great general similarity, in a north-westerly and south- 

 easterly direction, of the peculiar geological features of the Cordil- 

 lera belt. The coast mountains where crossed by the Stikine, and 

 again still farther north in the line of the Chilkoot Pass, consist for 

 the most part of granitoid rocks, which are generally rich in horn- 

 blende and triclinic felspars. With these are occasionally included 

 belts of crystalline schists, micaceous or hornblendic, the rocks as 

 a whole resembling those of which details are given in my last re- 

 port on Vancouver Island {Annual Report of the Geological Sur- 

 vey, 1886). It may be said, in fact, that the composition and struc- 

 ture of the coast ranges is practically identical wherever they have 

 been examined, from the Eraser River to the head of Lynn Chan- 

 nel, — a length of nearly nine hundred miles. 



To the east of these ranges, the country to and including the 

 Rocky Mountains proper is chiefly characterized by the occurrence 

 and wide distribution of paleozoic rocks, which often closely re- 

 semble those provisionally named the Cache Creek Series in south- 

 ern British Columbia. They include limestones, quartzites, argil- 

 lites, slates, and schists, with a notable proportion of agglomerates 

 and other materials of volcanic origin, and are all pretty thoroughly 

 altered and hardened and considerably flexed. Near Dease Lake, 

 and again on the Pelly almost on the same line of strike, important 

 beds of serpentine occur, and the associated rocks in these and 

 many other places are preponderantly schistose and slaty, running 

 through a number of varieties, but closely resembling the schistose 

 and slaty rocks of Cariboo, and other gold-bearing districts to the 

 south, and here also yielding gold. 



These paleozoic rocks are interrupted by granitic areas, which 

 generally rise in the form of ridges or mountain elevations, and 

 were in some places observed to be flanked by more or less consid- 

 erable occurrences of crystalline schists, which appear to be more 

 highly altered portions of the paleozoic. The most important of 

 these inland granitic ranges is that previously referred to as the 

 Cassiar Range. Granitic mountains also, however, occur in the 

 range to the east of Frances Lake, and elsewhere. 



Fossils are by no means abundant in the paleozoic rocks ; but a 

 small collection of graptolites was obtained on the Dease, which 

 has been submitted to Professor Lapworth, and by him pronounced 

 to be of middle ordovician age, six species being recognized. This 

 is, no doubt, the farthest north-western occurrence of a graptolitic 

 fauna so far noted on the continent. Carboniferous fossils, notably 

 Fustilina and Loftusia Columbiana, were obtained from lime- 

 stones in the Liard basin, and again on Tahko or Tagish Lake near 

 the head of the Lewes River. It is probable, however, that rocks 

 ranging from the Cambrian to the top of the paleozoic, and possi- 

 bly also including the triassic (Vancouver or Nicola Series), may 

 be embraced in this great preponderantly paleozoic area. 



Strata which are probably of cretaceous age occur on the Stikine 

 in limited basins immediately to the east of the coast mountains ; 

 and rocks holding middle or lower cretaceous marine fossils have a 

 considerable development on the Lewes, where they are associated 



