Scapular bones not visible externally. Pectoral fin, broad, separated by a rounded triangular space from the operculum, nearly straight above, rounded below, composed of eleven rays, the two lower soft and simple. Ventrals, consisting each of a stout spine, with the base sheathed in the integument. Pelvic bones, very narrow and pointed backward, thickly covered by integument. Dorsal spines, 5 or 6 (in so far as observed, 5 in the female, 6 in the male); short, stout, and with broad, triangular membranes; anterior spine shortest; spines usually only partially erected, and, when depressed, concealed in the dorsal groove; second dorsal of ten rays, second and third longest; the others rapidly diminishing toward the posterior end of the fin. Anal fin with one detached, curved, stout, membraned spine in front, in form similar to dorsal, and with ten rays. Caudal fin, broad at base, even posteriorly, of fourteen rays. First dorsal spine, above the insertion of the pectoral fin; last, above the beginning of the anal fin. Colour above, dull dark olive, with irregular darker blotches; abdominal region and lower part of gill-covers, pearly gray. Whole body dotted with minute black points. Male darker than female.

This species is found plentifully in most of the small streams near Montreal. Its food appears to consist principally of minute worms and crustacea. Its armature of spines and quickness in hiding enable it to inhabit with safety very shallow and exposed places; but it is easily taken with a dip-net, and great numbers are captured by young anglers for bait. It is easily kept in aquaria, finding its food in the minute inhabitants of the water, if a few tufts of algae are kept to shelter and feed them. It has however the bad character of attacking and destroying other small fishes with its formidable spines.

I am indebted to Mr. Putnam, assistant to Prof. Agassiz in the Museum of Comparative Anatomy at Cambridge, for comparing this species with specimens in that collection or described in the United States. It is nearly allied to G. millepunctatus of Ayres.

I am indebted for the outline in Figure 1, to Mr. R. J. Fowler, who has been so successful in representing our larger Canadian fishes.

ARTICLE XXV.-On Some of the Glacial Phenomena of Canada and the north-eastern Provinces of the United States during the drift period. By Professor ANDREW C. RAMSAY, F.R.S., F.G.S., Local Director of the Geological Survey of Great Britain.

(From the Journal of the Geological Society of London.) Glacialized condition of the Laurentine Mountains; and the drift-deposits of Montreal.-In the Straits of Bellisle, the barren coast of Labrador consists partly of low patches of red sandstones, &c., lying almost horizontally on the Laurentian series-that most ancient system of gneiss and granite which forms the eastern extromity of the great Laurentine chain. These gneissic rocks are rounded and largely mamillated, as if by the action of ice; and all the distant hills, quite bare of trees, possess the same sweeping contours. The gnarled strata of the lofty Bellisle itself, to the very summit, show unequivocal signs of the same abrasion, their well-worn outcrops presenting none of those jagged outlines that all highly-disturbed beds are apt to assume when exclusively weathered by air, rain, and open frost. Similar forms prevail far up the St. Lawrence, on its north shore, easily distinguishable in spite of the forests which, before we reach the Saguenay, rise to the tops of the mountains, leaving here and there unwooded rocky patches. Further up the river, by the Isle aux Coudres (about 50 miles below Quebec), I became more and more impressed by similar appearances. Not a peak is to be seen; and to the top every hill seemed moutonnée. Like much of Wales, Ireland, and the Highlands of Scotland, the country appeared moulded by ice.

On the south side of the river the country is low, being formed of Silurian strata chiefly covered with drift from the Laurentine chain; and the vast quantity of boulders and smaller stones that cover the land help to impress on it a poor agricultural character.

Approaching Montreal, the gneissic mountains recede to the northwest; and both banks of the river are low, except where an occasional boss of greenstone pierces the Silurian strata. Montreal Mountain, about a mile behind the city, is one of these, rising boldly out of the terraced drift of the plain.

This drift consists of clay, with Laurentian boulders and boulders of greenstone from the mountain, both mixed with subangular gravels of Utica slate and Trenton limestone, which formations rise on its flanks. Many of the boulders and smaller stones are grooved, or more finely scratched, in a manner undistinguishable from the scratched stones of the British and Alpine drift or of Alpine

Fig. 1.-Diagram-section of the Drift Deposits at Montreal

River
St. Lawrence.

Mr.Moffat's

Garden.

Dorchester St..

Montreal Mountain.

Marshy ground with concentrated boulders.

Trenton

2. Drift-beds of clay and boulders, cut into Terraces.

5.

Greenstone.

3. Utica Slate.

Limestone.

glaciers. We are indebted to Dr Dawson of Montreal for the three important subdivisions of the superficial deposits,—namely, 1st, at the base, lower boulder-clay and gravel; 2ndly, an unctuous clay, with many marine shells, called by him the "Leda-clay" (Led-Portlandica), on which lie, 3rdly, beds of gravel and sand, with shells, one of the most common of which is Saxicava Rugosa. These subformations occasionnally pass into each other where they join. The Saxicava sand he considers to have been a shallow and sublittoral deposit; the Leda-clay to have been accumulated at depths of from 100 to 300 feet or more; and the true boulder-clay to have been formed at an earlier period of subsidence, during which an ocean spread over the greater part of North America. I shall have occasion to show that at one time this sea was, in places, probably over 3000 feet in depth. The section (fig. 1)* across the drift, which I drew at Montreal, nearly agrees with Dr. Dawson's, with the exception that I show five terraces in the drift, while he gives two. Their number may vary in different localities; but they have certainly been formed during the last emergence of the country, each terrace indicating a pause in elevation; and in a great degree the shells of the upper strata lie in a debris of remodelled drift. The two upper terraces, to the left of

• For the Silurian geology of this diagram, I am indebted to the des

cription of Sir Wm. Logan.

Dorchester Street, correspond to Dr. Dawson's Leda-clay and Saxicava-sand.

Between the lowest terrace and the river there is a broad marsh, including patches of recent freshwater shells. It is part of the old course of the St. Lawrence; and on its surface (the lighter drift having been removed) the boulders that once studded the clay have been concentrated. Similar terraces occur on the banks of the Ottawa. The country is strewn with boulders of gneiss and metamorphic limestone, from the neighbouring Laurentine chain, mixed with more local debris; and here also it seemed, in several cases, as if, by removal of the lighter material, the boulders were more concentrated on the lower than on the highter terraces. Many of the blocks are rounded; in this respect differing markedly from the majority of those on glaciers, in moraines, and probably from those transported by icebergs, which, derived from glaciers that reach the sea-level, obtaiu their debris by the fall of rocks and stones on their surfaces from inland cliffs. In the American hills which I saw, there are no signs of true glaciers like those of the Alps having existed; and the boulders have been transported by floating ice from old sea-shores, where they had been long exposed to the washing of the waves.

At Hawksbury Mills I crossed the Ottawa with Sir William Logan, and penetrated part of the Laurentine hills lying several miles from the north bank of the river. Waterworn gravel here and there rises nearly to their summits, now rarely more than 500 or 600 feet above the river.

In the range about eight miles north of the Ottawa, there are well-rounded and occasionally grooved surfaces of gneiss greenstone, and quartz-rock, the striations, where I saw them, running 100 and 209 W. of S.

In many places, among the hills, numerous half-rounded boulders (of the same substances as those that strew the plains of the Ottawa and the St. Lawrence) cover the ground, and appear as if they had been waiting their turn for glacial transportation, ere the country was raised above the sea. These general signs existing in this chain, in latitude 4519 N., gave me more perfect confidence in the universal glacial abrasion of the hills on the coast of Labrador in a latitude nearly 150 miles further north.

Glacial Drift of the Plains; Stria and Roches moutonnées. -I need not indulge in repeated descriptions of the drift that covers the plains of Canada and the northern States. It is

enough to say that the descriptions given by previous writers are strictly correct. The whole country is literally covered with drift, -to such an extent, indeed, that except in denuded water-courses and deep gorges, like those of the Genesee and Niagara, it is only in rare cases that the rock is exposed. Even railway-cuttings rarely penetrate to the rocks below. It may be compared, in Europe, to the northern plains of Germany. In horizontal extension it is the most widely spread of all deposits; and even in thickness it rises to the dignity of a great formation, having by Logan and Hall been estimated in places at 500 and 800 feet in thicknesst. In all cases the Laurentian boulders, which have often travelled hundreds of miles, are mixed with fragments of the rocks that crop out northward towards the Laurentine hills, and with stones from the strata of the immediate neighbourhood,—the number of the component materials of the drift thus generally increasing to the south, marking the fact that the lowlands as well as the mountains have been subject to the denuding and transporting agency of ice. At a distance from the mountains, the boulders become comparatively few; and it is this admixture of calcareous and other material, often lightened with sand, that fertilizes the soil in the great plains that surround the lakes.

The City of Ottawa stands on Trenton limestone; and the surrounding country is strewn with boulders of Laurentian gneiss and Trenton limestone itself, and of Potsdam sandstone, &c.

Between Ottawa and Prescott on the St. Lawrence, the basement-rock is rarely seen. The country is chiefly covered with gravel containing boulders of gneiss from the hills, and of Silurian rocks from the plains. Here and there are patches of sand containing pebbles and small boulders, generally rounded. In some places it has the appearance of blown sand,-an effect that may have been produced as the land emerged from the sea.

The shores of Lake Ontario, in general, consist of low and shelving slopes of drift; but at Scarborough bold cliffs of sand, gravel, and clay partly white with boulders, rise 320 feet above the lake. The terraces of Toronto have been described by Sir Charles Lyell. They are like those of the St. Lawrence and the Ottawa. The lower part of the city stands on a very stiff boulder-clay, containing large and small boulders, many of them scratched. Somewhat higher there are beds of beauti

† I had an opportunity of examining the drift in many places between Quebec and London (which lies between Lake Huron and Lake Erie) about 500 miles from N.E. to S.W. in a direct line, and from north to south between Montreal and Ottawa, to Blossburgh and New York. See Murray's Report, Geological Survey of Canada, 1856.