VI.-River St. Lawrence above Quebec, and Ottawa Valley. Quebec and its Vicinity.-The deposits at Beauport, near Quebec, were described by Sir C. Lyell in the Geological Transactions for 1839; and a list of their fossils was given, and was compared with those of Montreal in my paper of 1859. As exposed at the Beauport Mills, the Post-pliocene beds consist of a thick bed of Boulder-clay, on which rests a thin layer of sand with Rhynconella psittacea and other deep-water shells. Over this is a thick bed of stratified sand and gravel filled with Saxicava rugosa and Tellina. In a brook near this place, and also in the rising ground behind Point Levi, the deep-water bed attains to greater thickness, but does not assume the aspect of a true Leda clay. Above Quebec, however, the clays assume more importance; and between that place and Montreal are spread over all the low country, often attaining a great thickness, and not unfrequently capped with the Saxicava sand. At Cap a la Roche the officers of the Geological Survey have found a bed of stratified sand under the Leda clay. The Beauport deposit is evidently somewhat exceptional in its want of Leda clay, and this I suppose may have been owing to the powerful currents of water which have swept around Cape Diamond at the time of the elevation of the land out of the Post-pliocene sea. The layer of sand at the surface of the Boulder-clay is evidently here the representative of the Leda clay, and affords its characteristic fossils, while the stones projecting above the Boulder-clay are crusted with Bryozoa and Acorn-shells. At St. Nicholas, there is a sandy Boulder-clay, not unlike that of Rivière-du-Loup, which has afforded some very interesting fossils. It is stated in the Report of the Survey to be one hundred and eighty feet. above the sea. Montreal.-In the neighbourhood of Montreal very interesting cxposures of the Post-pliocene beds occur, and with the terraces on the Mountain have been described in my papers of 1857 and 1859. I may here merely condense the leading facts, adding those more recently obtained. An interesting section of the deposits is that obtained at Logan's Farm, which may be thus stated in descending order: Gray sand, a few specimens of Saxicava rugosa, Mytilus edulis, Tellina Grænlandica, and Mya arenaria, the valves generally united,....... ft. in. 1 9 0804 0 8 1 1 1 3 Tough reddish clay, a few shells of Astarte Laurentiana, and Leda truncata, Gray sand, containing detached valves of Saxicava rugosa, Mya truncata, and Tellina Grænlandica: also Trichotropis borealis, and Balanus crenatus; the shells, in three thin layers. 0 8 Sand and clay, with a few shells, principally Saxicava in detached valves... Band of sandy clay, full of Natica clausa, Trichotropis borealis, Fusus tornatus, Buccinun glaciale, Astarte Laurentiana, Balanus crenatus, &c. &c., sponges and Foraminifera. Nearly all the rare and deep-sea shells of this locality occur in this band,...... Sand and clay, a few shells of Astarte and Saxicava, and remains .... ..... .... 0 3 ......... of sea-weeds with Lepralia attached; also Foraminifera,... 2 0 Stony clay (Boulder-clay). Depth unknown. In this section the greater part of the thickness corresponds to the Leda clay, which at this place is thinner and more fossiliferous. than usual. Along the south-east side of the Mountain, and in the city of Montreal, the beds have been exposed in a great number of places, and are in the aggregate at least 100 feet thick, though the thickness is evidently very variable. The succession may be stated as follows: 1. Saxicava Sand.-Fine uniformly grained yellowish and gray silicious sand with occasional beds of gravel in some places, and a few large Laurentian boulders, Saxicava, Mytilus, &c., in the lower part. Thickness variable, in some places 10 feet or more. 2. Leda Clay-Unctuous gray and reddish calcareous clay, which can be observed to be arranged in layers varying Some of these layers have usually Foraminifera and slightly in colour and texture. surface of the clay in places where it has not been denuded before the deposition of the overlying sand, there are many species of marine shells. A few large boulders are scattered through the Leda clay. 3. "Boulder-clay.—Stiff gray stony clay or till, with large boulders and many glaciated stones, often of the same Trenton rocks which occur on the flanks of the Mountain. It is of great thickness, though it has been much denuded in places, and has not been observed to contain fossils. It is especially thick at the south and south-west sides of the Montreal Mountain. The Montreal Mountain, like other isolated trappean hills in the great plain of the Lower St. Lawrence, presents a steep craggy front to the north-east, and a long slope or tail to the south-west; and in front of its north-east side is a bare rocky plateau of great extent, and at a height of rather more than 100 feet above the river. This plateau must have been produced by marine denudation of the solid mass of the Mountain in the Postpliocene period, and proves an astonishing amount of this kind of crosive action in hard limestones interleaved with trap dykes, and which have been ground and polished with ice at the same time that the plateau was cut into the hill. By ice also must the debris produced by this enormous erosion have been removed, and piled along the more sheltered sides of the hill in the Boulderclay. With regard to the crag-and-tail attitude of Montreal Mountain, I have to observe that in large masses of this kind reaching to a considerable height, and rising above the Post-pliocene sea, the north-east or exposed side has been cut into steep cliffs, but in smaller projections of the surface over which the ice could grind, the exposed side is smoothed or moutonnée," and the sheltered side is angular. A little reflection must show that this must be the necessary action of a sea burdened with heavy floating icc. The most strongly marked terraces on the Montreal Mountain, are at heights of 470, 410, 386, and 220 feet above the sea, but there are less important intermediate terraces. On the highest of these, on the west side of the Mountain, over Cote des Neiges village, there is a beach with marine shells, and on the summit of the Mountain, at a height of about 700 feet, there are rounded surfaces, probably polished by ice, though no striation remains, and large Laurentian boulders, which must have been carried probably a hundred miles from the Laurentian regions to the north-east, and over the deep intervening valley of the St. Law rence. . I have already, in the first part of this memoir, noticed the striation on rock surfaces at Montreal, and may merely add that it is often very perfect, and must have been produced by a force acting up the St. Lawrence valley from the north-east, and planing all the spurs of the Mountain on that side, while leaving the Mountain itself as a bare and rugged unglaciated escarpment. In the streets of Montreal the true Boulder-clay is often exposed in excavations, and is seen to contain great numbers of glaciated stones, most of which are of the hardened Lower Silurian shales and limestones of the base of the Mountain; and though no marine shells have been found, the sub-aquatic origin of the mass is evidenced by its gray unoxidised character, and by the fact that many of the striated stones at once fall to pieces when exposed to the frost, so that they cannot possibly have been glaciated by a sub-aerial glacier. At the Glen brick-work, near Montreal, the Leda clay and underlying deposits have been excavated to a considerable depth, and present certain remarkable modifications. The section ob served at this place is as follows: 1. Hard gray laminated clay, Foraminifera and Leda, in thin 2. Red layer, in two bands 3. Sandy clay... 4. Gray and reddish clay.... 5. Hard buff sand, very fine and laminated. 6. Sand with layers of tough clay, holding glaciated stones, 7. Fine sand.... 0 8. Gray sand, with rounded pebbles, and laminated ob- 9. Fine laminated yellow sand 3 0 10. Gravel...... 0 4 11. Very irregular mass of laminated sand, with mud, gravel, stones and large boulders 12 0 56 10 The whole of these deposits except the Leda clay, are very irregularly bedded, and are apparently of a littoral character. They seem to shew the action of ice in shallow water before the deposition of the Leda clay. The only way of avoiding this conclusion would be to suppose that the underlying beds are really of the age of the Saxicava sand, and that the Leda clay has been placed above them by slipping fram a higher terrace; but I failed to see good evidence of this. A little farther west at the gravel pits dug in the terrace for railway ballast, a deep section is exposed showing at the top Saxicava sand, and below this a very thick bed of sandy clay with stones and boulders, constituting apparently a somewhat arenaceous and partially stratified equivalent of the Boulder-clay. A little above this place, at the Brick works, the Saxicava sand is seen to rest on a highly fossiliferous Leda clay, which probably here intervenes between the two beds seen in contact nearer the edge of the terrace. Ottawa River.-The Leda clay and Saxicava sand are well exposed on the banks of the Ottawa; and Green's Creek, a little below Ottawa City, has become celebrated for the occurrence of hard calcareous nodules in the clay, containing not only the ordinary shells of this deposit, but also well-preserved skeletons of the Capelin (Mallotus) of the Lump-sucker (Cyclopterus) and of a species of stickleback (Gasterosteus). Some of these nodules also contain leaves of land plants and fragments of wood, and a fresh-water shell of the genus Lymnea has also been found. At Packenham Mills west of the Ottawa, the late Sheriff Dickson found several species of land and fresh-water shells associated with Tellina Groenlandica and apparently in the Saxicava sand. These facts evidence the vicinity of the Laurentian shore, and indicate a climate only a little more rigorous than that of Central Canada at present. They were noticed in some detail in my paper of 1866 in The Canadian Naturalist.. The marine deposits on the St. Lawrence are limited, as already stated, to the country east of Kingston; and the clays of the basin of the great lakes to the south-westward have, as yet, afforded no marine fossils. I have, however, just learned from Prof. Bell, of the Geological Survey, a discovery made by him in the past summer and which is of very great interest, namely that two hundred miles north of Lake Superior the marine deposits reappear. The details of this important discovery will be given in a forthcoming Report of the Geological Survey, |