A subsequent change, in the surface of the country, is indicated by the marks of attrition and watery action upon the faces of these rocks, in situations greatly elevated above the present water-levels. This action must, consequently, be referred to a period when extensive submersions, in the nature of lakes or semi-seas, existed; for there is no power in present lakes and streams, however swelled and reinforced by rains or melting snows, to reach even a moiety of the elevation of these ancient water-marks. It is to the era of these last submersions that we are encouraged, by evidences, to look, as the disturbing cause which has buried trees, leaves, and bones in alluvial soils.
Action of Water.—In examining some portions of the flat lands of Ontario County, such as the township of Phelps, there are strata of a fine sedimentary soil, such as might be expected to result from the settlings of water not greatly agitated. The bottoms of mill-ponds afford an analogous species of soil. In these level districts, there are also not unfrequently observed fields of bare flat rock, of the limestone species, which is checkered in its surface, conveying the idea of their having formed a flooring to some former lake. An appearance of this kind may be seen a few hundred yards from the meeting-house in Phelps. The rock, in this instance, is a carbonate of lime, and affords organic remains.
The Oak Openings, in Erie County, are a kind of natural meadows or prairies. Many suppose them to have been ancient clearings; but of this the Indians have no tradition, and the evidences of such a settlement are by no means satisfactory. In many places, on these extensive openings, there are naked and barren layers of calcareous rock, whose surface exhibits appearances analogous to those in Ontario. The limestone is, however, of a darker color, and contains numerous imbedded nodules of hornstone, and it emits a fetid odor on breaking.
In crossing the elevated calcareous highlands, between Danville and Arkport, in Steuben County, we perceive in the bluff rocks which bound the valley of the Conestoga River, at an elevation of perhaps two hundred feet above its bed, horizontal water-marks, deeply impressed upon the face of the rocks, as if the waters had formerly stood at that level; and it is impossible to resist the conviction, in travelling over this rugged district of country, that it has not been totally submerged by waters, which have been suddenly drawn off, but by gradual or periodical exhaustions, standing for many ages at different levels.
Slate Rocks.—These were, not inaptly, denominated "brittle slate," by Dr. Mitchell, in 1809. Brittleness is their pervading character; and it is owing to this quality, in a formation of great thickness, that the action of the water at Niagara Falls is of so very striking a character. There is no portion of the Niagara slate solid enough to be used for building stone. It is uniformly shelly, and exhibits, even in hand specimens, its reproduced character.[ [243] Those portions of the general formation which are solid constitute silicious slate. A locality of this variety may be seen at the Halfway House, eight miles east of Canandaigua.
Seneca Lake.—This clear and picturesque lake has its bed in the secondary formations, and may be referred to as exhibiting localities of them. Its upper parts afford the compact limestone in quadrangular blocks. Large portions of its margin consist of the brittle carbonaceous slate. The shores, from the vicinity of Rose's Farm to Appletown, are little else but a continuous bank of the slate. On the opposite coast, it is also visible at various localities below the Crooked Lake inlet. Cashong Creek may be particularly referred to. A short ascent of its valley brings the spectator into a scene where the walled masses of slaty rock assume a character of grandeur. Among the recent portions which have been thrown into the valley, may be seen masses having large species of the stem-like organic remains, which indicate its newness as a formation. Here are also disclosed orbicular masses, and pebbles of other rocks, imbedded in the slate. These prove it to be—what its texture would, in other places, indicate—a secondary slate.
The order of position on the banks of this lake is the same as at Niagara; but the sandstone is not apparent above the water line. Its existence, in the bed of the lake, may be satisfactorily inferred, from the masses of yellow coarse sand which are driven up at the foot of the lake, and particularly around its outlet. When the winds prevail, the water is driven violently against this part of the shore. As it is an alluvial flat, they soon surmount the stated margin, and produce a partial inundation. On their recession, wreathes of sand remain.
Diluvial Elevations.—Bounding the alluvial plain of the Seneca outlet westward, there is a series of remarkable wave-like ridges, whose direction is parallel to that of the lake. On the declivity-stop of the first of these ridges, stands the village of Geneva, the buildings of which are thus displayed in an amphitheatric manner above the clear expanse of the lake. The substratum of these ridges is an argillaceous, compact soil of the eldest formation. Some parts of it are a stiff clay, and yield septaria; but there is no considerable portion of it, which has been examined, wholly destitute of primitive boulders and pebbles. Little doubt can remain but that it is the result of the broken-down slaty rock mixed with the extraneous and far-fetched primitive masses. They are conclusive of its diluvial character. I have attentively examined this formation, in the section of it exposed on the shores of the lake between the village of Geneva and Two-mile Point. All its solid, stony contents are piled along the margin of the lake, the soil being completely washed away. Granite, quartz, and trap pebble-stones and boulders, are here promiscuously strewn with recent debris. Over the argillaceous deposit is spread a mantle of newer soil, of unequal depth and character, which forms, exclusively, the theatre of farming and horticultural labors.
White Springs.—On the declivity of one of these parallel ridges, at the distance of two miles from the lake, is found an extensive bed of white marl. This deposit, which is on the estate of the late Judge Nicholas, covers many acres, and yields so copious a spring of pure water that it is sufficient, at the distance of about three hundred yards from its issue, to turn a gristmill. There are to be found in this bed of marl several species of helix and voluta. The marl is generally covered with an alluvial deposit of two feet in depth. The depth of the marl itself is unexplored. Is not this marl the result of decomposed sea shells?
Beds of Quartzose Sand.—In certain parts of the Seneca Valley are found limited deposits of a white quartzose sand, in a state of comparative purity. This substance is capable of being readily vitrified by the addition of alkaline fluxes, and is thus converted into glass. Its existence, as a local deposit, beneath separate strata of alluvial soil, supporting a growth of trees and shrubs, is such as to render it probable that the present stream, in its exhausted state, could have had no agency in producing these deposits. If we are compelled to look to a former condition of the waters passing off through this valley, as affording the requisite power of deposit, we are then carried back to an era in the geology of the country which we must refer to, to account for by far the greater number of changes in all its recent soils. Indeed, wherever we examine these soils, out of the range comprehended between high- and low-water mark, on any existing lake or stream, there will be found occasion to resort to the agency of more general and anterior submersions. A few localities may be appealed to.