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related in structure, substance, or mode of occurrence, to the Graptolites, at least so far as regards American species; and the Nemapodia is not a fossil body, nor the imprint of one, but simply the recent traces of a slug over the surface of the slates. The genus Rastrites of Barrande has not yet been recognised among American Graptolitideæ. These forms are by Geinitz united to his genus Cladograpsus, the propriety of which we are unable to decide.

The genus Gladiolites (Retiolites of Barrande, 1850; Graptophyllia of Hall, 1849) occurs among American forms of the Graptolitidea in a single species in the Clinton group of New York. A form analogous with the reticulated margins and straight midrib has been obtained from the shales of the Hudson River group in Canada, suggesting an inquiry as to whether the separation of this genus, on account of the reticulated structure alone, can be sustained. In the meantime we may add that the Canada collection sustains the opinion already expressed, that the Dictyonema will form a genus of the family Graptolitidea. The same collection has brought to light other specimens of a character so unlike anything heretofore described, that another very distinct genus will thereby be added to this family. The Canadian specimens show that the Graptolites are far from always being simple or merely branching flattened stems.

The following diagnosis will express more accurately the character of the genus Graptolithus:—

Genus GRAPTOLITHUS (Linn.)- Description.-Corallum or bryozoum fixed (free?), compound or simple, the parts bilaterally arranged, consisting of simple stripes or of few or many simple or variously bifurcating branches, radiating more or less regularly from a centre, and in the compound forms united towards their base in a continuous thin corneous membrane or disk formed by an expansion of the substance of the branches, and which in the living state may have been in some degree gelatinous. Branches with a single or double series of cellules or serratures, communicating with a common longitudinal canal, affixed by a slender radix or pedicle from the centre of the exterior side.

The fragments, either simple or variously branched, hitherto described as species of Graptolithus, are for the most part to be regarded as detached portions from the entire frond.

In the living state we may suppose those with the corneous disks and numerously branched fronds to have been concavo-convex (the upper being the concave side), or to have had the power to assume this form at will. In many specimens there is no evidence of a radix or point of attachment, and they have very much the appearance of bodies which may have floated free in the ocean.

Exploration of British North America. Report on Geology by Dr HECTOR.-Fort Edmonton, Saskatchewan, January 10, 1859.-I have the honour to make the following report of my geological observations during the past season, in which is embodied only the principal results and general features of the country examined, the details being reserved for a more elaborate study and comparison than can be executed here. On starting from Fort Carlton on 14th of June 1858, we crossed the low track of prairie land which is bounded to the west by that line of high ground which has been traced from longitude 103° W. sweeping to the NEW SERIES.-VOL. XI. NO. I.—JAN. 1860.

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N.W. to meet the south branch of the Saskatchewan at the elbow, known as the "Coteau des Prairies," and from that point being continued to the north branch as the Bad Hills and Eagle Hills, while across that river it reappears as the Thickwood and White Lake Hills. The average elevation of these plains above Carlton (which is built upon the first river level, thirty-five feet above the water) is 250 feet, or 2125 feet above the level of the sea, and on it rests isolated portions of the higher level which have survived the general denudation, rising as rounded hills from 300 to 400 feet in height, such as Moose Hill on the south branch, and the two Minetonass Hills (Creefor Hill by itself), one of which is opposite to Carlton and the other to Forte à la Corne. These plains are plentifully strewn with erratic blocks of all sizes, being fragments of the rocks of the Granitic belt, which runs to N. W. from Lake Superior to the Arctic Sea, with others of Magnesian limestone and buffcoloured quartzose rock of Silurian age, which crops out all along the western flank of that range. A very remarkable line of the Magnesian limestone boulders occurs at the distance of twenty miles above Carlton, crossing the country from the Thickwood Hills in a southerly direction, towards the Moose Hills on the south branch. This limestone contains the same indistinct fossiliferous markings as that at the Stoney Hill behind Fort Garry. Some of these masses are of immense size, being made up of portions of several beds which only loosely cohere to form the block. They are all sub-angular, without any glacial markings, although some have their sides highly polished and smoothed from the buffalo rubbing against them. One of these blocks was measured, and computed to be 140 tons. The nearest known point where this limestone occurs in situ, from whence these blocks may have been derived, is 170 miles distant to N.E. Disregarding, for the sake of clearness, the order in which the country was examined, I now give at once an account of the whole "drift" phenomena observed. As we travelled to the west, the drift was found to preserve the same mineral character of variable proportions of sand and clay, having boulders interspersed, but chiefly with the clay predominating. The boulders, however, decrease in size, and those of limestone become very rare as the higher plains are gained. At Fort Edmonton, for instance, I found it difficult last winter to procure fragments with which to make lime for medicinal purposes, although the river bed is strewn with those of other rocks. Its depth also becomes much less, forming only a superficial covering to older strata, when observed in the river sections to the west of the Eagle Hills. As we approached the Rocky Mountains it quite disappears from the table-lands, and is only to be found in depressions of the plain through which streams run; and even the existence of true drift in these places is rendered doubtful, owing to the prevalence of more recent deposits, which have been formed of its rearranged materials. At the altitude of 4000 feet above the sea, and at the distance of fifty miles from the mountains, there however occurs a very extraordinary group of blocks of granite, resting upon a high plateau, formed of sandstone strata, to be afterwards mentioned. These blocks are of great size, one having been estimated to weigh 250 tons. Although lying miles apart, they seem to consist of the same rock-viz., a mixture of quartz with red felspar, the latter predominating, with only faint traces of mica disseminated in very minute flakes.

No granitic rocks have been met with on this side of the watershed of the mountains, and it is not probable that any such exist, at least between the two branches of the Saskatchewan. These blocks present smooth surfaces, although in general they are rhomboidal in form. Some are cracked into several pieces, which are quite detached, but have evidently at one time formed part of a whole. If these blocks were derived from the granitic belt to the east, as I believe all the other boulders on the plains to have been, then they must have travelled at least from 400 to 450 miles. From the fact, however, that they are almost on the western verge of the drift deposit, and that the boulders imbedded were found as a rule to diminish in size in that direction, it may be that the presence of these large blocks is due to very different agencies, different at least in the time of their occurrence. Close in, along the base of the mountains, neither on the high plateaus nor in the profound valleys by which these are traversed was there observed any traces of the drift, or its dispersed erratics. Within the outer range of the mountains, which are comparatively low, and wooded to their summit, the valleys are occupied by immense deposits of rounded shingle, composed of fragments of the various rocks which have been found to compose the mountains. This shingle, which in some places is loose, and mixed with a large proportion of sand and gravel, in others is cemented by calcareous matter into a solid conglomerate. It fills up the valleys not only along the edge of the mountains, but also right into their interior, forming beautifully marked terrace levels along the streams. This is well exhibited on the north branch of the Saskatchewan, where these deposits skirt its wide valleys for nearly seventy miles of its course through the mountains, expanding where it widens so as to form extensive plains, as at the Kootanie plain, and always affording a margin of level ground along the river, rendering the road very practicable. Towards the upper ends of the valleys the calcareous matter of these deposits so increases as to replace altogether the shingle, when it becomes a fine gritty calcareous mud, of glistening whiteness. This same deposit has a much larger development in the valleys on the west side of the watershed, forming terrace levels in exactly the same manner. I observed no shingle beds with it there, however,these apparently being replaced by fine sand and gravel. In the valley of Bow River, there is much less of this calcareous matter in the deposit, it having more of a loose sandy nature, and except at the entrance to the valley in the neighbourhood of the Bow Fort, rarely exhibiting the terrace levels. In the smaller gorges, where streams come down from the mountains, it is replaced by an angular "breccia," of which patches cling in the most singular positions. This latter deposit is most likely of the nature of glacier moraines, although it is found where no glacier occurs anywhere in the neighbourhood. I found, however, that the glaciers in the chain had at one time extended a considerable degree beyond their present limits, and therefore, at that time they possibly may have existed in portions of the mountains where now there are none. The terrace deposits seem to reach pretty nearly the same altitude in different parts of the mountains-viz., about the height of 1000 feet above the level of the plains at their eastern base. I found that, in crossing the different heights of land, the easiness of the pass corresponded with the degree to which these deposits had remained untouched,

owing to peculiarities in the form of the valleys. In the case of every height of land, whether of those examined by Captain Palliser or by myself, with the single exception of the Vermilion Pass, the slope is gradual to the east, but to the west the descent is with extreme rapidity. This arises from these deposits having being scooped out close up to the rocky nucleus of the height of land, by currents acting from the western side of the chain, while on the east the erosion has been much more feeble. How much this may depend on the difference between the width of the valleys which pass through the flanking chains on the east side of the height of land from those on the west I am not prepared to say, until the nature of the country to the west has been ascertained. Currents acting on the chain while submerged, would of course be greatly modified in their action by any such differences. Respecting the age of these deposits I am in doubt. They extend towards the east along the river valleys at least shingle deposits of the same nature are found at a considerable distance from the mountains, in the valleys of the north and south branches, and of the Red Deer River. Its relations to the drift have not been distinctly ascertained, as the boulders which mark its presence are only in that district of country found on rounded knolls away from the rivers.—Papers relative to the American Exploration, 1859.

PUBLICATIONS RECEIVED.

L'Institut for August, September, October, and November, 1859.— From the Editors.

Natural History Review for October 1859.-From the Editors.

Proceedings of the Manchester Philosophical Institution-(continued). -From the Society.

Natural History of the European Seas, by Prof. E. Forbes and R. G. Austen.-From the Publishers.

Journal of the Asiatic Society of Bengal, No. 2, for 1859.-From the Editor.

Canadian Journal of Industry, Science, and Art, for November 1859. -From the Editors.

Reply to Sir David Brewster's Memorial to the Lords Commissioners of Her Majesty's Treasury on the New Series of Dioptric Lights, by D. and T. Stevenson, Civil Engineers.-From the Publishers.

Martins, Charles, Du Froid Thermométrique et de ses Relations avec le Froid Physiologique dans les Plaines et sur les Montagnes.-From the Author.

THE

EDINBURGH NEW

PHILOSOPHICAL JOURNAL.

On Gebel Haurán, its adjacent Districts, and the Eastern Desert of Syria, with Remarks on their Geography and Geology.* By JOHN HOGG, M.A., F.R.S., F.L.S., &c.

The Rev. J. L. Porter, M.A., F.R.G.S., being for several years a resident missionary in Damascus, took the opportunity in February 1853 of visiting the Lejah and the Haurân; and he gave to the world a very interesting account of the same in his amusing work, entitled, "Five Years in Damascus ;" which was published two years afterwards. In the spring of 1857, my friend, Mr Cyril Graham of Trinity College, Cambridge, became acquainted with Mr Porter in Syria, and having heard much from him respecting the Haurân, he resolved to go and explore it. Accordingly, in the summer of that same year, Mr Graham travelled through it. But, since that remarkable region is already known by the able descriptions of Porter, Buckingham, Burckhardt, and Seetzen, it will be unnecessary for me to add any particular account of it, except a short notice of its geology. That portion itself chiefly comprised, under the Arabic name of the Haurân, the Auranitis of the Greeks, will, in Mr Graham's words,-" Ever claim the most solemn

This paper was in part read to the Geographical Section of the British Association, at the meeting held in Aberdeen, on September 15, 1859.

NEW SERIES.-YOL. XI. NO. II.-APRIL 1860.

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