the coal fields of Pictou County, but as yet no sufficiently detailed survey permits the expression of a decided opinion. In Pictou County their thickness was estimated by the Geological Survey at 5,567 feet in the district lying south of New Glasgow. The Coal Measures north of the Conglomerate are estimated by Dr. Dawson to be 670 feet thick, and to represent probably the upper part of the productive measures lying south of New Glasgow.

Passing over the small outlier of productive measures in Antigonishe County, said to hold workable seams of coal, the Richmond district is met. Here, according to Mr. Fletcher's report, the coal seams of Little River are contained in no less than 8,926 feet of strata, curiously associated with limestone and gypsum, recalling the Coal formation rocks of Wallace and River John, as described in Acadian Geology.

In Cape Breton County the ravages of the Atlantic have left 1,750 feet of productive measures, and evidence is not wanting to show that is not far from their original maximum thickness. In Newfoundland the highest known divisions of the Carboniferous, paralleled in the geological survey of that Island with the productive measures of Cape Breton, have a thickness estimated at 1,300 feet.

It is to be noticed that in the Eastern end of the area the conditions of level were not continued under circumstances favouring the formation of productive measures as long as in the western districts. And it is in those districts in which the depression was most prolonged that we find the succeeding horizon.

The measures holding the Little River Coal beds, in Richmond County, appear from their higher dips to have undergone folding prior to the deposition of the overlying series now presented as a synclinal with low dips. The disturbances of the productive measures in Pictou County were finished toward their close, for we find the Upper Coal formation lying conformably on the productive measures north of New Glasgow, and both are undisturbed by the numerous folds into which the productive and the preceding Carboniferous measures are thrown south of that village. Similar foldings of a more local character took place at Springhill, where the productive measures appear to pass unconformably under the edges of the Upper Coal formation, in a series of east and west, and transverse folds like those of the Pictou district.

It may now be remarked that allusion has been made to the folding and disturbance of large areas in New Brunswick and Cape Breton, and in Cumberland and Pictou Counties. We find similar foldings impressed on the Carboniferous horizons south of the Cobequids. In the absence of direct evidence, it may be conjectured from the comparatively undisturbed state of the Upper Coal measures, and Permo-Carboniferous, where found to the north, that their foldings were contemporaneous with some of those alluded to above, and that they were not deferred to the close of the Carboniferous.

THE UPPER COAL MEASURES.

These measures appear in the district extending from Antigonish through Pictou, Colchester, and Cumberland Counties to the Joggins. At this place they are conformably deposited as the upper member of the great Carboniferous series, and attain a thickness of 2,267 feet. About twenty miles to the east they appear to lie unconformably on the middle coal measures at Springhill, as already mentioned. They pass thence in an almost

unbroken series into Pictou, where their thickness is estimated by Dr. Dawson at 2,500 feet. He also points out that these measures graduate upwards into beds having a Permian aspect, and suggests the term Permo-Carboniferous for their upper portion. In this paper they are considered together, as the same remarks apply to both. These beds are also found in Prince Edward Island, and extend across the strait to New Brunswick, and are presented in shallow synclinals.

In the Richmond district there is a set of measures which present some evidence of unconformability to the horizon holding the Little River coal beds, and may represent the upper coal measures. They lie in a shallow basin, and are of limited extent; their thickness is about 1,350 feet.

In the Pictou and Cumberland district these measures are bent in folds, generally with low angles, the date of which cannot now be fixed by superimposed strata. The folding of the Cape Breton coal field, with its low and broad synclinals is of a similar character, and may have been synchronous. It may be considered that these foldings took place before the Trias, or toward the close of the Permo-Carboniferous. Since this date the Carboniferous measures have undergone some changes of level consequent on the deposition of the Trias, and its elevation, and the continental depressions which have left their record in rock grooving and travelled boulder. These changes, however, except locally, in the case of the Trias of the Bay of Fundy, do not appear to have greatly affected the Carboniferous, for we find the interior of New Brunswick, the Millstone Grit of Dorchester, the Upper Coal Measures and Permo-Carboniferous of Cumberland, Pictou, and Prince Edward Island lying in positions indicating slight movements, except those of a continental character.

Prior to the opening of the Carboniferous period the rocks of Nova Scotia were folded in regular east and west folds which have been explored and mapped in the iron ore and gold-bearing districts, and the regularity of their folds and other evidence would tend to show that they have not been greatly disturbed since that date. The Carboniferous measures were unconformably deposited on these strata, and their long period permitted a maximum accumulation of strata reaching 22,000 feet.

During this time, in addition to the continental changes of level, giving rise to conditions of deposition characterizing the Carboniferous limestone, Millstone Grit, etc., there were extensive foldings of a more local character, apparently in some cases marking the closing of these oscillations. These foldings and their subsequent denudations have played an important part, hitherto but little studied, in modifying the conditions arising from the longer and more extended movements which have hitherto principally received attention, and present the district as being far from any universal state of quiet and regular succession during the Carboniferous era.

V.-Note on the Triassic of the Rocky Mountains and British Columbia.

By GEORGE M. DAWSON, D.S., F.G.S.

(Read May 25, 1883.)

The Triassic rocks of the West present themselves under two very dissimilar aspects, their eastern part consisting of red beds, chiefly sandstones, while on the Pacific slope the character of their material is much more varied; they include numerous fossils, and are evidently truly marine in origin. The most complete comparison of these two classes of deposits has been made by Clarence King in the 40th parallel region. The red beds are there found participating in the Rocky Mountain uplift, but have originally passed completely across the position of this range, and extend westward to the Wahsatch Mountains (longitude 112°) which here constituted the western shore of the sea in which they were deposited. The rocks are described by King as consisting generally of sandstones, the upper half being always of lighter colours than the lower, and intercalated more or less with beds of dolomite and gypsum. The lower part of the series is usually from brick to vermilion red, the upper part pale red and buff. The dolomitic and gypsum beds are local in character, but the latter sometimes reach forty feet in thickness of pure calcic sulphate.

In the Rocky Mountains, in this latitude, the Triassic is from 300 to 1000 feet in thickness but, on approaching the Wahsatch shore, thickens to 2000 or 2500 feet, and holds some conglomerates. Fossils are almost completely wanting.

In many other districts of the western States and Territories, the Triassic beds are developed with similar characters. As far east as the Black Hills of Dakota, they are described by Professor N. H. Winchell as maintaining a thickness of over 300 feet, and holding great quantities of white gypsum. They have been observed by Dr. Hayden in the mountains at the head waters of the Missouri, and in addition to the deposits of gypsum are in places impregnated with salt.

Returning to the 40th parallel region, and passing westward from the Wahsatch range, no Triassic beds are met with till longitude 117° 30' is reached, at a distance of nearly 300 miles. The rocks of this period are there found to be represented by the Star Peak and Koissats groups of King, the former and upper subdivision consisting of fossiliferous limestones, with quartzites and slates, the latter of quartzites, argillites and porphyroids, the whole with an aggregate thickness of over 16,000 feet. Marine fossils are very abundant in some parts of the Star Peak subdivision, and are almost precisely similar in forms with those of the St. Cassian and Hallstadt beds of the Alps. The term Alpine Trias has consequently often been used in speaking of those rocks.

The red beds of the Rocky Mountain region clearly point to the conditions of deposition found in a shallow body of water, more or less completely shut off from the ocean or only in occasional and brief connection with it, while, for the most part, the sediments of the Nevada Triassic are, as unmistakably, such as might be produced under ordinary marine conditions in greater or less proximity to a coast line.

The distinction thus marked is clearly encountered much further south than the 40th parallel region, and it is with the purpose of tracing it to the north of the 49th parallel that the present note is presented.

Immediately to the north of the 49th degree of latitude, in the Rocky Mountains, about the South Kootanie Pass, the red beds are characteristically developed, with a thickness of about 300 feet. The upper portion of the section in this part of the mountains, is as follows, in descending order:—

Series H. Fawn-coloured flaggy beds, seen only at a distance, but from their appearance and analogy with Series F, probably thin-bedded dolomitic sandstones and limestones. Throughout 100 feet.

Series G. Beds characterized by a predominant red colour, but including some thin, greyish layers and dolomitic sandstones. The whole generally thin-bedded. Ripple marks sun-cracks, impressions of salt crystals. 300 feet. Passes gradually down into

Series F. Fawn-coloured flaggy beds of dolomitic sandstone and limestone, with more red sandstone layers, which are especially abundant toward the top. 200 feet. Series E. Amygdaloidal trap. 50 to 100 feet.

The last mentioned immediately overlies the compact bluish limestone of Carboniferous age, and, with the exception of the interruption caused by this contemporaneous sheet of volcanic matter, the whole of the series are conformable and pass gradually each into the

next.

The conditions indicated are, in Carboniferous times, a somewhat deep sea gradually shoaling. The occurrence of an important volcanic outbreak, and shortly thereafter the more or less complete closure of the communication of this area with the ocean and the formation of the Triassic inland sea.

Westward from this region similar beds may be traced by information supplied by Mr. H. Bauerman, for about forty miles, but beyond this point they have nowhere been observed in British Columbia. Northward, along the main range of the Rocky Mountains, I have observed them for about fourteen miles only, beyond the 49th parallel. They were not seen by me in the Crow Nest Pass, in latitude 49° 30', nor anywhere along the eastern base of the mountains from this point to the Bow Pass (latitude 51°) or in that pass. Neither have they been noted by Dr. Hector in any part of the Rocky Mountains to the north of the Bow which he traversed, or by Dr. Selwyn in the Yellow Head Pass. While, therefore, the evidence so far adduced is purely negative, it would appear that the Triassic inland sea in this longitude found its northern shore not far beyond the 49th parallel, and probably never extended west of the Selkirk and Gold Ranges of Central British Columbia.

Still further north, however, we meet with evidence of a more decided character. For, on the upper Pine and Peace Rivers, on the eastern flank of the mountains, a series of blackish shales and argillites, sometimes calcareous, occur, and hold characteristic Alpine Trias fossils. Beds containing similar forms are found in a number of places to the west of the Gold Range in British Columbia, and it is probable that the Triassic ocean, in the latitude of the Peace River, extended completely across the Cordillera belt eastward. No mountain boundary occurs between this region and that first described to the south, but a tract of probably low land must have separated these two areas in the Triassic period. In the Queen Charlotte Islands Triassic rocks, holding fossils of the same strictly

marine character, are largely developed, and they also occur with abundant molluscous remains in the northern part of Vancouver Island. In the southern part of the interior of British Columbia, not far west of the Selkirk and Gold Ranges, rocks also occur uncon formably overlying the Carboniferous series, from which a few fossils, with little doubt, belonging to the same Alpine Trias fauna have been obtained; and it is further probable that as in California-the greater part of the auriferous shales are attributable to this or the succeeding Jurassic series.

In the Queen Charlotte Islands, Vancouver Island, and on the mainland of the province, however, the Triasic series is largely composed of rocks of volcanic origin, some of which have been lavas while others are agglomerate or ash beds, made up of fragments of igneous material, more or less perfectly stratified. These are mingled with schistose and slaty rocks, and in some places with massive bluish lime-stone, deposited during periods of tranquillity; and it will require the most careful and systematic examination to completely separate this from the underlying strata. I have little doubt that the so-called 'porphyroids' of King's Koipato group indicate an extension of similar volcanic activity over the 40th parallel region to the south.

A word may be added with reference to the climatic conditions implied by the Red Beds of the interior. The basin in which they were formed has not only been pretty completely cut off from the ocean, but the rate of evaporation of its waters must have been normally in excess of that at which they were re-supplied by precipitation or drainage from neighboring lands. It is probable that at that time, as at the present day, westerly winds prevailed in this part of the northern hemisphere, and, if the North Pacific Ocean then existed, these would carry, as they do now, an abundance of moisture and afford a copious rainfall on the west coast. As the land barrier of the inland sea to the west cannot have been of very great width, it must have been of such height as to cause the almost complete desiccation of these oceanic winds by precipitation before they reached the area occupied by the Triassic Mediterranean; and this old mountain range, must, in British Columbia, have occupied nearly the position of the Selkirk and Gold Ranges of to-day, at a time when the Rocky Mountain region proper was still a flat expanse of Palæozoic rocks.

To the north, at the present time, between the 54th and 56th parallels, the Gold Range almost completely disappears, and it is through this gap that the Triassic ocean must have flowed eastward to the upper Peace River country and, perhaps, much farther east-though the Cretaceous, and Laramie beds, occupying the flat country, render it impossible to trace its deposits in that direction.