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effected by the combined action of air and water. The group occupies a very considerable, but irregular territory. It appears occasionally in small beds, then dips beneath the surface, and again appears, as the surface rock, over an extensive tract. In the forms of Potsdam sandstone, calciferous sandrock, birdseye and Trenton lime. stone, and Utica slate, it bounds the great primary region of the northeast in every direction, varying in width from two to fifty miles. It also makes its appearance in narrow beds on either side of the Hudson.

The Ontario Group, which comes next in order, consists of three distinct portions; the lowest a marly sandstone, generally soft, and either red, green, brown, or variegated, -decomposing rapidly, when exposed to the atmosphere, and denominated Medina sandstone ; next, a series of soft, green, slaty rocks, also easily decomposed, and overlaid by clayey and finty limestones, alternating with each other, and finally terminating in the limestone over which the Niagara pours its resistless cataract; and lastly a group of limestones, containing gypsum or plaster of Paris, water lime and salt, known as the Onondaga salt group:

This group, considered with reference to practical purposes, is the most valuable of the transition system in the state. It includes the salt springs in Salina and its vicinity, and at Montezuma, which yield so large an amount of revenue to the state ; the gypsum beds, which furnish such inexhaustible resources for the fertilization of the soil, as well as for the various purposes of the arts, to which this valuable mineral is applied; and the water lime, called, after its preparation, hydraulic cement, a material indispensable to the proper construction of canals, aqueducts, cisterns, and other masonry exposed to the action of water, and one which has proved of the greatest service in the construction of the public works of the state.

The fossils of this group are numerous and interesting. Shells of bivalve molluscous animals, corallines and madrepores, together with unequivocal traces of vegetable existence, mark this era.

Its minerals are not numerous. The clayey limestones contain iron ore; fuor spar and selenite appear occasionally, and sulphur springs gush up from different sections. Its soil is of unsurpassed and perpetual fertility, being constantly enriched by the slowly decomposing lime and gypsum. It is the granary of the state, and before the wide prairies of the west waved with the golden grain, it supplied nearly the whole country with bread-stuffs. The oak, beech, maple, elm, butternut, hickory and black walnut, are the principal forest trees. The Ontario group commences at the southwest. ern extremity of Lake Ontario in Canada, and extends eastward with a medium breadth of twenty miles to its termination in Montgomery county.

The Helderberg series comprises four kinds of limestone and three of sandstone. Of these the Helderberg limestone is extensively used as a flagging stone, under various local names; it is also employed to some extent as a building material; the Oriskany sandstone is also used as a building material; it occasionally contains lime. Of the remaining layers, one of the sandstones is dark, shaly and brittle; the other calcareous and abounding in fossils. Two of the limestones contain large quantities of fossils, and derive their names from that fact ; in one the encrinite, one of the most beautiful of the crustaceous fossils, is predominant; in the other, the pentamerus, whose shell bears some resemblance, in form, to that of the common oyster. The remaining limestone is slaty and easily decomposed.

The Helderberg limestone is cavernous, and many of its caves have been explored for a considerable distance. They contain stalactites and stalagmites of great beauty.

The principal minerals of this formation are bog iron ore, calcareous and fluor spar, jasper, sulphate of strontian, in great abundance, satin spar, alum, bitumen and small veins of anthracite. The soil, overlying these rocks, is generally either a fine clay, or sand lying upon clay. Marl occurs quite frequently. By suitable cultivation it yields good crops of wheat and other grains. The timber is usually vak, chestnut, hickory, pine and hemlock.

This group occupies a narrow tract, commencing in the western part of Orange county, and passing northeasterly through Ulster to the Hudson ; thence along the banks of that river, to Albany county, where it turns westwardly, passes through the centre of the state immediately south of the Ontario group, forming the bed of most of the small lakes in western New York, and terminates on the shores of Lake Erie.

The Erie Group is divisible into two portions, the lower, denominated Ludlowville shales, is composed of soft slaty rocks, alternating with thin beds of limestone, and is easily decomposed; the upper, called the Chemung group, consists of thin, even beds of gray sand. stone, with intervening shales, or beds of slate.

Some of the fossils, found in this group, possess great beauty, and show the approach to that period of vegetable luxuriance, which marks the coal formation. Ferns, and other vegetable fossils frequently occur, and the avicula, delthyris and other shell fish, strongly resembling some living species, are found imbedded in the rocks.

The minerals of this group are few, and of no great importance. Petroleum, or mineral oil, called, in some parts of the state, Seneca oil, occurs in several localities, and the shale is often so strongly impregnated with it as to burn quite freely. Carburetted hydrogen, or inflammable gas, also issues from the surface in a number of places, and in such quantities, as to be used, in one or two instances, for illuminating villages, light houses, &c.

The soil where the Ludlowville shales form the surface rock, though apparently rough and broken, is rendered fertile by the constant decomposition of the rock. It is well adapted to the culture of wheat and other grains. As we ascend, to the more elevated surface of the Chemung sandstone, we find a marked change in the character of the soil; the white pine and hemlock take the place of the oak, maple and beech of the lower lands, and attain a gigantic growth. These lands produce the grasses luxuriantly, and, as they become cleared, will afford pasturage to vast herds of cattle and sheep.

The Erie group covers nearly the whole of Chautauque, Cattaraugus, Wyoming, Allegany, Steuben, Yates, Tompkins, Chemung and Tioga counties, together with portions of Broome, Chenango, Cortland, Ontario, Livingston, Genesee and Erie, as well as a narrow tract in Sullivan, Ulster, Greene, Schoharie and Otsego counties.

This completes what, for convenience, has been termed the New York Transition system. The remaining group properly belongs to the Transition system of the English Geologists, and is by them denominated the Old Red sandstone, that rock being its principal constituent. The State Geologists, from the fact of its being the predominant rock of the Catskill mountains, have given it the name of the Catskill group.

It consists of two distinct formations, viz., the Old Red sandstone overlying the Chemung sandstone, and the conglomerate strata, which are immediately beneath the coal bearing limestone of Pennsylvania. Between the layers of the former are interposed soft shales combined with mica.

The sandstone is generally of a deep red color, and imparts the same hue to the soil which covers it. It contains comparatively few fossils; the scales and bones of some lizard-like fish have been discovered in it.

The minerals of this group are few, and of but little importance. Bog iron ore and calcareous spar are those most worthy of notice. The conglomerate affords fine grindstones, and has been used to some extent for millstones.

The soil is generally good; the sandstone decomposing readily under atmospheric influence, mingles with the vegetable mould and renders it fertile. Hemlock, beech, maple, elm, basswood, butternut, &c. are the principal timber trees; the oak is seldom found in this formation.

The Red sandstone of the Catskill group is mostly confined to the vicinity of the Kaatsbergs; occupying the county of Delaware, and portions of Sullivan, Ulster, Greene, Otsego, Chenango and Broome; but the conglomerate extends westward, and caps the highest hills of the southwestern counties.

The Diluvial deposits skirt the shores of the St. Lawrence, Lake Champlain, and the Hudson, and compose the surface of the northern half of Long Island. They consist of a stiff blue clay beneath, a yellowish brown clay above this, and sand on the surface. The marine shells, found in these clays, belonging in some instances to extinct species, show that these deposits were made at an earlier period than those thrown down by rivers or oceans, in modern times. To this system belong also the boulders, scattered so widely over the state.

The Alluvial deposits, consisting of gravel, sand, loam, &c. thrown up by the waves, or deposited on the shores of lakes, and the banks of rivers, and still in the process of aggregation, constitute the last of the geological formations of the state. To these belong portions of the valleys of the rivers and lakes and the southern half of Long Island. The soil of both these classes of deposits is usually fertile.

The class of rocks known as trap and porphyry, do not, in this state, constitute a separate formation. They occur either in columnar masses like the Palisades, on the west bank of the Hudson, near New York, or in narrow veins or dikes, traversing rocks of an entirely different constitution. They are evidently the result of the action of subterranean fire. Porphyry is only found occupying a tract of a few miles in length, on Lake Champlain.

In connexion with the Geology of the state, the “Ridge road” is deserving of notice. This road consists of a bank of sand,

gravel and

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other alluvial and diluvial deposits, varying in height from 100 to 150 feet, and extending along the whole southern coast of Lake Ontario, at a distance of six or eight miles from it, forming a natural highway. It is said that a somewhat similar ridge exists along the northern shore of the Lake.

That this ridge once, and at no very distant period, formed the south. . ern shore of the lake, is proved, by the existence of small sand hil. locks, evidently heaped up by the action of the waves; by the entire absence of Indian mounds and fortifications, on the north side of the ridge, and their frequent appearance, immediately south of it; and above all, by the structure and composition of the ridge itself.

The deep channels, cut in the rocks, by many of the rivers of the state, are also a subject of geological interest. The Hudson, St. Lawrence, Oswego, and some of the northern streams, either have banks regularly sloping to the water's edge, or, if they occasionally pass through narrow and precipitous defiles, have not won for themselves a passage, by the action of their waters upon the rocky barrier which opposed them, but have availed themselves of a route opened by some convulsion of nature.

Such is not the case with the Mohawk, the Chenango, the Genesee, and the Niagara. Descending from elevated table lands, they have, by their ceaseless flow, hewn out a channel through the shales, slates and marly sand and limestones, in some instances 400 or 500 feet below the level of the surrounding country. The constant action of the waters upon these decomposing rocks has also caused the falls of Niagara to recede, as some geologists conjecture, a distance of five or six miles, and this recession is still in progress.

MINERALOGY. We have already adverted to the minerals, pecu. liar to the different formations, but a somewhat more particular description of the mineral wealth of the state seems requisite, in a work like ours.

Among the useful metals, Iron is most abundant in New York. It is found in five forms.

1st. The Magnetic Oxide, most abundant in Essex, Clinton, Franklin, Warren, Orange and Putnam counties, but occurring also in considerable quantities in Lewis, St. Lawrence and Jefferson. This variety is adapted to the production of malleable iron and steel, and for this purpose is superior to any in the United States, and equal to most of the foreign ores. The quantity is immense, a single vein (the Sandford vein in Newcomb, Essex county,) being estimated by Prof. Emmons to contain ore sufficient to yield at least three millions of tons, of malleable iron ; several other veins, in the same neighborhood, contain nearly as much more, and the mines of Orange county, though worked for nearly a century, are still very productive. This ore is confined to primary rocks.

2d. The Specular Oxide, found in St. Lawrence, Jefferson and Franklin counties, imbedded in sandstone. This variety is well adapted to castings. Though less abundant than the preceding, it is found in large quantities.

3d. The Argillaceous ore, called also bog iron ore, found in vari. ous parts of the state, evidently deposited by alluvial and diluvial action, in the clay or gravel. It is principally used for castings.

4th. The Hematitic ore, frequently occurring in crystals of fantas. tic and beautiful forms. This ore occurs extensively in Richmond, Orange, Ulster, Putnam, Dutchess, Columbia, Warren and Wayne counties. It is also found in smaller quantities in Rockland and Westchester. It usually makes its appearance in the lower limestones of the transition system. When combined with the magnetic oxide, it improves its quality.

5th. The Carburet of Iron, called also Black lead, Plumbago and graphite, occurs abundantly in Dutchess county, and in considerable quantities in Essex and Clinton counties.

Lead is found, in immense quantities, at Rossie and its vicinity, in St. Lawrence county, and less abundantly in the Shawangunk moun. tains, in Sullivan and Ulster, and in Dutchess, Columbia, Lewis and Monroe counties. It does not seem to be confined to any particular geological era, occurring in nearly all the formations.

Zinc and Copper occur in various parts of the state, but not in sufficient quantities to be of much practical value.

Arsenic has been discovered in Putnam county.

Manganese, in the form of manganese wad, occurs in Columbia, Lewis and Dutchess counties, and is used to some extent for bleaching. Manganesian garnet is found in New York county.

Barytes and Strontian are abundant in Schoharie and Jefferson, and probably exist in some of the other counties.

Alum, principally in the form of efflorescence, is found in several parts of the state.

The existence and value of the deposits of gypsum, and water lime, has already been noticed, in speaking of the Onondaga salt group.

Serpentine and its allied minerals, soapstone, talc, carbonate, hydrate and sulphate of magnesia, (Epsom salts,) together with asbestus and amianthus, occur abundantly in Putnam, Orange, Westchester, Jefferson and St. Lawrence, and in considerable quantities in Monroe, Orleans, Genesee, Albany, Cayuga, Essex, Rensselaer and Niagara counties.

Those minerals, which are only of interest to the mineralogist, are enumerated under the counties in which they occur.

MINERAL SPRINGS. These are of various kinds.

1. Chalybeate Springs. The most celebrated of these, are those of Saratoga county, which are fully described in another part of the work. There are a few, but of no great strength or notoriety, in other parts of the state.

2. Sulphur Springs. These are widely disseminated. Those at Avon, in Livingston county, have attained the greatest celebrity. Those in the vicinity of Rochester, Monroe county, and Chittenango, Madison county, are perhaps next in importance. The State Geologists report sulphur springs in twenty-eight counties of the state.

3. Brine Springs occur in every part of the Onondaga salt formation, and are also found, though of less strength, in other parts of the state. They are supposed to be impregnated by deposits of rock salt, at some distance below the surface. Those in the towns of Salina and Montezuma are the most important and valuable.

4. Acid Springs, or those in which the water is strongly impregnated with sulphuric acid, are found in Genesee, Erie and Orleans counties.

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