crystalline. It is well defined as a formation by a considerable number of characteristic fossils. The Guelph dolomites form beautiful building stones, and they have been largely used for this purpose in Galt, Guelph, Elora and Fergus. They also burn to lime of excellent quality.

ONONDAGA (SALT) FORMATION.

Economics.

Nature of for

Distribution.

This formation is named after Onondaga in the state of New York, and is celebrated for its salt-bearing character. It consists principally of yellowish and drab colored dolomites and greenish and drab shales, with some reddish mation. layers, especially near the base of the formation. It occurs along the east shore of lake Huron from Goderich to the mouth of the Saugeen river, from which it turns east and south, rounding the northern end of a wide synclinal between Southampton and the head of Owen Sound, and running thence south-easterly to the Grand river, from which it takes an easterly course to the Niagara. The numerous borings which have been made through the formation in search of salt in the country to the east of lake Huron prove it to have a thickness of 775 feet at Goderich and 508 feet at Kincardine, Thickness. but this has diminished to about 300 feet where it crosses the Niagara river above the falls. The beds of rock-salt which furnish the brine of Salt. the wells at Kincardine, Wingham, Blyth, Clinton, Goderich, Exeter, Seaforth, etc., occur towards the base of the formation and are only reached by deep boring. The bore-holes for some of these salt wells have also passed Gypsum. through deposits of gypsum. Beds of this mineral occur likewise along the Grand river from a short distance above Paris to near Cayuga. Most of it is of a grey color, useful as a mineral manure, but in some places it is white enough to calcine for stucco and alabastine. One of these localities is the Merritt mine, where there is a bed of white gypsum four to six or seven feet in thickness. Further particulars of these deposits, contained in the evidence collected by the Commission, are published in another part of this report.

stone.

In this formation on the east side of the Saugeen. river, just above Walkerton, the writer in 1861 discovered lithographic stone of excellent Lithographic quality, but breaking transversely into pieces of too small size to be of much value. The band forms the top of the bank of the river, and the beds associated with it burn into a remarkably white lime.

Moose river.

On Moose river, banks of gypsum occur from ten to twenty feet high, especially on the north-west side below the junction of the Missinaibi, for a space of about seven miles, or from thirty-one up to thirty-eight miles above Gypsum on Moose Factory. About ten feet of the lower part of the deposit consist of solid gypsum of a light bluish grey color, but the upper portions are mixed with marl. In some sections of these banks a comparatively small proportion of the gypsum, but still large commercially speaking, is nearly white, and from this circumstance they have received the name of "the white banks." The geological age of these deposits cannot be far from the Onondaga formation, and it would not be surprising if salt should also be found in the rocks with which they are associated.

Waterlime division.

Old and New red sandstones.

LOWER HELDERBURG FORMATION.

A portion of the Waterlime division of the Lower Helderburg formation of the state of New York reaches the township of Bertie on the Ontario side of the Niagara river, but as it is unimportant and closely connected with the Onondaga formation, it requires no further description in the present short sketch.

THE DEVONIAN SYSTEM.

This system, which derives its name from Devonshire in England, was at one time called the Old Red Sandstone to distinguish it from the Permian, which was known as the New Red Sandstone. Some geologists have advocated changing the name in America to "Erian," but there seems to be no sufficient reason for this, and as Sir William Logan followed the method of calling the systems by their British names and the formations by those adopted in the United States, we prefer to adhere to an uniform plan of nomenclature, and to continue to recognise the well established name of this system. The Devonian rocks are important in various countries, from holding deposits of petroleum, salt, gypsum and iron ore, and they are also of interest geologically from the fact that it is among them that the remains of fishes and land plants first Red sandstones. became abundant. Red sandstones form a prominent feature in the Devonshire rocks of the eastern part of the Gaspé peninsula in Quebec, but they are absent from them in the province of Ontario. This system occupies a con. siderable area in the western peninsula and again in the northern part of the province, and in both of these regions the Corniferous formation constitutes its most prominent member.

Economics:

Sandstone.

Distribution.

Nature of formation.

Thickness.

This is the lowest in the Devonian system, and is represented in Ontario by only about twenty-five feet of coarse grey and brownish sandstone. It is exposed in various places along the base of the next higher formation between the township of Windham and the Niagara river. It has been used as millstones for the preparation of oatmeal, and also for building purposes.

The Corniferous formation is so called from the nodules of hornstone which it frequently encloses. Its base or lower border runs north-eastward from near Goderich to the township of Greenock, where it turns around the north end of the wide synclinal already referred to, from whence it takes a southward course to the township of Burford, and then strikes eastward to the township of Bertie. The shore of lake Erie from the outlet of the Niagara river to Port Rowan lies upon this formation. Its junction with the overlying Hamilton formation is covered with superficial deposits, but it is supposed to run northward from near Port Rowan, keeping at a distance of twenty to twenty-five miles from the line above described as marking the base of the formation.

In western Ontario it consists mostly of grey limestone, containing great numbers of fossil corals, some of which form masses of considerable size. It makes a fair building stone, and is also burnt for lime. Borings for wells in south-western Ontario have given the following thicknesses for limestone sup

posed to represent the Corniferous in each case: Port Lambton, 320 feet; Petrolia, 248 and 378; one mile south-west of Belle river, 209; Leamington, 310. In such borings, however, it is difficult to draw a line between the limestones of this formation and those of the underlying Onondaga.

The petroleum of the Enniskillen field is drawn directly from the Corniferous limestone, but it has not been proved that it originated in these rocks. There are reasons for supposing it to be quite as likely that the oil comes up from the underlying Trenton formation.*

In the region south-west of James bay the Corniferous formation occupies an area greater than all the western peninsula of Ontario. A large part

Petroleum.

region.

of this, lying between the Albany river and the basin of the Moose river, comes within the northern part of the province. It consists mostly of porous James bay and cavernous drab grey and yellowish grey fossiliferous limestones resting directly upon the Archæan rocks to the southward, the line of junction cutting the Missinaibi river just below Hell-gate, the Mattagami just below the Long Portage, and the Abittibi just below "The Otters" portage. Many of the Corniferous fossils of this district belong to species which differ from those of the formation in regions to the south of the height-of-land, tending to show that there was here a separate basin in these early times as well as now. At the foot of Grand rapid on the Mattagami river the writer, in 1875, discovered a large deposit of rich clay-ironstone in these rocks. The materials of the Drift, for a considerable distance to the southward of the Corniferous formation in this region, contain fragments of this ore, indicating that it exists, and probably in the same horizon, among these rocks in many other places besides the above mentioned locality on the Mattagami.

HAMILTON FORMATION.

Clay ironstone.

formation.

This is not called after the city of Hamilton, but a village of the same name in the state of New York. It consists of bluish and drab grey clays or Nature of marls, called "soapstone" by the well-borers, with some greyish limestones, and occasionally an arenaceous band. The total thickness of the formation in Ontario is estimated to be about three hundred feet, of which the lower 170 or 185 feet are found below the Drift clay and above the Corniferous limestone in the oil territory of Enniskillen. This impervious rock has served to prevent the upward escape and loss of the petroleum and gas of this region in past ages.

CHEMUNG AND PORTAGE FORMATION.

This is represented in Ontario by a few feet of black bituminous shales in the southern part of the county of Huron and the northern part of Lambton. Blick shales. A narrow border of the formation may also exist beneath the Drift on the north shore of lake Erie, between Rondeau and Port Talbot. In the states of New York, Pennsylvania and Michigan these rocks are, however, extensively developed, and constitute an important formation.

*The Petroleum Field of Ontario," by Dr. R. Bell in the Transactions of the Royal Society of Canada for 1887, page 109.

+Report of the Geological Survey for 1875-76, page 321.

The Post Tertiary period.

Evidences of glacial action.

Escarpments, how formed.

Origin of deep bays.

THE POST TERTIARY SYSTEM.

The rocks which have been described in the foregoing pages comprise all the ancient or fundamental formations represented in Ontario, the remainder of the geological scale which is so largely developed in various other parts of the world being entirely wanting till we come to the Post Tertiary period, which includes our superficial deposits such as boulder-clay, stratified clay, sand, gravel, etc. The oldest of these is called the Drift.

THE DRIFT.

In a previous part of this section a description was given of the extensive glaciation which took place in the Archæan regions of Ontario during the Drift period, so that it will be unnecessary to dwell further on that part of the subject. The glacial phenomena are also very noticeable throughout the Paleozoic districts, so that everywhere in the province the surfaces of the solid rocks bear the ancient ice-marks in the shape of flutings or furrows and grooves or striæ. With the exception of the high lands near the east coast of Labrador, no part of the Dominion on this side of the Rocky mountains, as far as known, appears to have escaped the action of glaciers in the Drift period. The rocks in the Archæan districts are everywhere ground down and rounded, the evidence of the glacial action being usually as plain on the tops and sides of the hills as in the valleys. In the Paleozoic regions, where the strata lie almost horizontally, the wearing down of the rocks has taken place principally along the planes of bedding. Where the dip happens to be in about the same direction as that which was taken by this great denuding force, the excavations naturally deepened until a point was reached where the weight and solidity of the opposing rocks became sufficient to resist the ice-mass, and in this way escarpments have been formed. All the great lakes of the St. Lawrence, except lake Superior, lie in basins of erosion which have been hollowed out in the same manner. The basin of lake Superior, although its origin was of volcanic nature, has been much enlarged by glacial denudation. It has been shown that the lakes of our Archæan regions are all of glacial origin, and that most of them lie in rock-basins excavated during the Drift period. A few of them owe their existence to moraines or dams of glacial debris, which hold up their waters.

The fracturing of the sedimentary rocks along anticlinal lines has greatly aided glacial erosion, and in this way long bays have been formed in the geographical outlines of the formations, such as those on Manitoulin island, the Indian peninsula and thence to lake Ontario, and all along the base of the Black River formation from Matchedash bay to Kingston.

A marked difference is observable in the effects of glacial action on the opposite sides of the Archæan nucleus on which the Paleozoic strata rest. Valleys or water channels have been formed wherever the ancient glaciers plunged downward off the Archæan highlands upon the opposing edges of the newer rocks, as all along the southern boundary of the Laurentian and Huronian rocks of the province. But no such action took place when the glacial mass was forced up the gentle slope of the Paleozoic beds of the basin of Hudson bay and thence upon the Archæan plateau to the south of it.

Effects of the

Here we find no physical features to mark the line of contact between the two kinds of rock which differ so much from one another. On the east side ancient glaciers. of Hudson bay deep channels and valleys with high escarpments facing inland have been formed by the descent of the old west-moving glaciers against the up-turned edges of the Cambrian rocks along that coast, while on the opposite side of the bay they moved off the Devonian and Silurian rocks without leaving any impression on the geographical features of that region.

and paleozoic

In the metamorphic regions in the northern parts of Ontario, the rounded glaciated surfaces of the tops and sides of the hills have been left almost or quite bare in many parts, but in most districts and especially in Drift in the the Paleozoic areas of the province the smoothed and grooved or striated metamorphic rock-surfaces are covered by a thick deposit of stiff clay mixed with sand, regions. gravel, stones and boulders. This is known as drift, boulder-clay, hard-pan, etc. In Scotland it is called till, and this convenient name is now being adopted in America and elsewhere. On the higher grounds north of lakes Superior and Huron there is usually but little clay, the drift consisting of loose boulders, stones, gravel and sand.

phenomena.

The transportation of the boulders in the till, as well as those lying on bare surfaces, has been simultaneous with the planing and grooving of the Glacial rocks, and due to the same cause. An erroneous impression which is very prevalent attributes both these phenomena to icebergs. Although the latter may have brought some boulders and dropped them among the Post Tertiary clays and sands, they appear to have had little influence on the formation of the underlying till, and they have had nothing to do with the wearing down and grooving of the solid rocks. The ice-grooves are locally nearly parallel, except in cases where different sets cross one another. In pursuing their course they will go up one side of a rounded ridge or knoll of rock and down the other, or they may curve around it and even pass under overhanging rocks, grooving both the wall and roof in a manner quite impossible to have been produced by a floating iceberg. The glacial phenomena of the Drift period in these latitudes correspond in every way with what may be observed on a small scale in connection with modern glaciers, and there can be no doubt that they have been due to land ice. These phenomena occurred at this period in the north temperate zone all around the globe, and the gigantic scale on which they operated constitutes one of the most extraordinary phases of the earth's history. The prevalence of ice was so general at this time that it is also known as the Glacial Period.

movement.

The general direction of the glacial movement over Ontario, as shown by the striæ, was southward, but it varied greatly to the east and west of Direction of south in different regions. North of lakes Huron and Superior, and from the glacial the latter westward to Lake-of-the-Woods, it was generally south-westward, but in some instances it varied greatly from this on account of local causes. In the western peninsula it was south-eastward, but around lake Ontario south-westward; in the lower Ottawa valley south-eastward, but north of it the direction was south-south-westward. In the Eastern Townships it was south-eastward, while around Montreal the course was south-westward.

M. (4)