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dance of hydraulic power will be furnished, but the sandy character of the soil, more particularly upon the eastern slope, will sometimes render it difficult to secure from accident the dams which may be erected. The country north of the southern boundary of Arenac county and east of the meridian, so far as examined, is on the whole but ill adapted to the purposes of agriculture, being chiefly composed of sandy ridges with intervening swales, and rising so j towards the central portions of the state as to leave the country extremely flat. There are, however, many valuable tracts of white pine, which will serve to render this portion of the state of some importance, Yellow pine, well adapted for light spars, also abounds. A large portion of the immediate shores of the lake is composed of marsh, An exception to the flatness of the country exists in an elevated district commencing in high hills a little south of Thunder Bay river and stretching in a southwesterly direction towards the head of Lake Michigan. This range, at its commencement, is usually known as the highlands of the Au Sable. These hills follow the line of bearing of the rock formation, and no doubt extend diagonally completely across the state, forming a portion of the summit of the more northern part of the peninsula. The greater portion of the country, after passing the summit west of the meridian, is of a character totally different from that just described. From the site of old Mackinac, at the very extremity of the peninsula, south to the Manistee river, a direct distance of about one hundred and forty miles, the immediate shores of the lake are almost invariably considerably elevated, sometimes rising abruptly to a height of from three hundred to four hundred feet. The country, (more particularly the northern portions,) as we proceeded into the interior, continues to rise, until it attains an altitude probably quite equal, if not superior, to any other portion of the peninsula. This is more particularly the case in the vicinity of, and south east from Little and Grand Traverse bays. Here the surface is considerably broken by elevated ridges of limerock, which are, without doubt, a continuation of the line of bearing of the great limestone formation of Wisconsin. In proceeding south from Grand Traverse bay, the interior of the country would appear to become less elevated, or gradually to fall away to the southeast, while the elevation of the coast is increased; a circumstance which will serve to account for the eneral direction of the two principal streams, the Maskego and ão rivers. The elevated shores of Lake Michigan, which when viewed from a distance have the appearance of sand, are found in reality to be composed, except in the recent sand dunes, of alternating layers of a highly marly clay and sand.
The hilly limestone region to which allusion has been made, is mostly heavily timbered with beech and maple, and although portions of it are rather broken, it is as a whole admirably adapted to the purposes of agriculture. After leaving the limestone district, in passing south the country becomes more variable, the soil sometimes assuming a sandy character. The face of the country is also generally more level, although some districts are considerably rough. This northern portion of the peninsula is usually regarded by the inhabitants of our state as possessing too rigorous a climate to admit of agriculture, but this is an error which deserves to be corrected. The Ottawa Indians, residing on Little Traverse bay, and who have somewhat extensive cultivated fields in the elevated limestone district of the interior, more particularly in the vicinity of one of the southwestern forks of the Cheboigan river, inform me that their crops of corn have not sailed within their recollection to yield largely; and certainly I never saw finer corn than in some of their fields. The soil of these lands is strictly a “warm” one, and exposed as it is to the vivifying influences of the southern winds during the summer, it cannot fail to be productive. In this respect the country on the western slope is precisely the opposite of that on the northerly and easterly slopes, for this latter district is constantly subject to the chilling influence of the northerly winds from Lake Superior, an influence which even the most cursory observer could hardly fail to notice. This difference of circumstances, even were the character of the soil similar upon the opposite sides of the peninsula, could not sail materially to affect the value of the lands for the purposes of agriculture, adding to the
value of those of one district while it would detract from those of the other.
The examinations of the past year, in the northern and unsettled portions of the peninsula, have been wholly of a general character, and were made with a view of determining, as far as possible, the precise points to which the minute examinations can, hereafter, be directed with the greatest profit. These examinations cannot be completed in such a manner as to enable us to delineate the geology of that country upon our maps, until the United States' linear surveys be completed. These latter surveys, which during the past year have been extended as far north as town twenty-six, have nearly reached a portion of the peninsula, which, in a geological point of view, is possessed of the highest interest. Several parties of surveyors are now nearly in readiness to commence the work north of the town mentioned. and we confidently hope, that during the ensuing year the chief o ; the subdivisions which remain to be done, may be cometed. p It is not my intention, at this time, to enter into a minute des. cription of the order of superposition of the rocks, over the large area of country under consideration, nor would it be possible, were it desirable, to present the subject to you in such a shape as to render it intelligible without the aid of diagrams. The accompanying descriptions will, therefore, be almost exclusively confined to those points at which the out-crop of rock occurs under such circumstances that it may be made available for practical purposes, together with such suggestions as the circumstances may appear to warrant. The rocks of this northern portion of the peninsula may be regarded as referable to the great carboniferous group of the state, a position to which their fossil contents is amply sufficient to substantiate their claim. In this respect they coincide with the rocks heretofore described as occupying the southern counties; nevertheless, it must be borne in mind, as there stated, that these rocks occupy a very different position in the series. The rocks of the district under consideration consist of a succession of limestones, with intervening shales, sandstones and clays; and as we approach the very extremity of the peninsula, the limestone is shattered, in a manner similar to that exhibited by the sandstone in the southern counties of the state. The line of bearing of the members constituting this group of rocks, not only in the northern but likewise in the southern portion of the peninsula, is regularly northeasterly and southwesterly, a direction which it is believed the rocks upon the opposite side of Lake Michigan will also, at least to a certain extent, be found to pursue. The general characters of the separate portions of the group are preserved, in a remarkably distinct manner, at great distances, and the mineral contents are but little varied. My examinations would lead me to infer that the coal of the central portions of our state, and that upon the Illinois river, is embraced in a rock which belongs to the same portion of the great basin; a conclusion which, if borne out, will aid much in determining some important points, respecting the relation which the neighboring rocks bear to each other. I am also led to conclude that that portion of the rock series which, in Illinois and Wisconsin, embraces the ores of lead, is identical with a portion of the rock formation which occurs in the northern part of our own state; a circumstance which might fairly have been inferred from the general line of bearing of the rock. Whether this extension of the rock also contains that mineral, in sufficient quantities to be of any practical value, remains yet to be determined.
A slight glance at the map of our state will sufficiently explain the relation which Saginaw bay, of Lake Huron, holds to the line of bearing already mentioned. This great arm of that lake, stretches in a southwesterly direction, making a deep indentation in the peninsula, and occupying a denuded space in the sandstone just at that point where the latter comes in contact with the limestone of the north. Thus, while the southerly portions of the bay are characterized by the appearance of abrupt, but low cliffs of sandstone, which rock may be traced in a southwesterly direction completely across the peninsula, the opposite, or northerly shore, is not less marked by the occurrence of limerock, which stretches in a like manner, southwesterly to Lake Michigan. This limestone forms several of the headlands and small islands of Saginaw bay and Lake Huron, and also occasionally appears in the beds of the streams, giving rise to rapids near their places of embouchure. In proceeding northerly from the mouth of Saginaw river, limestone is first noticed, forming the very extremity of Point au Grais. Quarries have been opened here, and a rough building stone obtained. It is of compact structure, tolerably adapted to resist the action of the elements, aud being situated, as it is, in such a manner that the stone may be readily quarried and transported, it is a point from which the country in the vicinity of Saginaw river may be more economically supplied with this character of stone, than from any other. By judicious selection, portions of it may be made use of for the manufacture of lime, but the great mass is of too silicious a character to admit of use sor that purpose. Limestone still more silicious in its composition, occurs on the Charity islands, where it may be quarried to a limited extent, and will answer a good purpose for rough walls. The rock of these islands, for the reason already stated, will scarcely admit of being applied to use for the manufacture of lime. That at Great Charity island contains large quantities of embedded chert. Between Charity islands and the southerly cape of Thunder Bay, limestone appears at short intervals, but at such low levels (usually forming the bed of the lake,) as to be of no practical value. At this latter point the rock occurs in an abrupt cliff, which rises directly from i. water, to a height of from ten to twenty feet. and is continued for the distance of half a mile. The limerock alternates with layers of a fissile clay slate, the latter of which composes about two-thirds of the whole out crop. ping rock forming the face of the cliff. The limestone may be easily quarried, and portions of it would answer tolerably well for architectural purposes, but as a whole, in consequence of the irregular shapes into which the rock is liable to separate, it is of
At a distance of something less than two miles, southeast from the cliff just mentioned, a dark colored and highly bituminous shale occurs, forming a small island. This island, which, during the past season, in consequence of the high water, has been nearly submerged, is usually denominated Sulpher island. This bituminous shale, which is seen to extend a considerable distance around, forming the bed of the lake, dips below the limestone just described, and may be regarded as of no great thickness, Small specks and nodules of iron pyrites are embedded in it, and so completely is the whole mass saturated with bitumen, that when thrown upon “the fire,” it blazes freely. From this circumstance it has been mistaken for coal, and considerable quantities of it were actually shipped to Detroit, under this delusive supposition. Limestone is again seen in the bed of Thunder Bay river, at a distance of about one mile srom its mouth. Over the out cropping edge of the rock the waters descend in a series of very brisk rapids; and the stream is capable of furnishing a greater amount of hydraulic power, at this point, than has been noticed at any single place on the peninsula. Were it not that the sandy nature of the banks would render much care necessary in order to make the works secure, it might be very cheaply applied; and occurring as it does, near the mouth of a large stream, which will furnish a safe harbor for lake vessels, the great value of this immense power, for application to mechanical purposes, cannot fail to be eventually appreciated. Limestone was not observed at any point upon Thunder Bay river, sufficiently elevated, to admit of its being quarried. Lime rock also occurs at the northerly cape of Thunder Bay, the Thunder Bay islands and Middle island, as also at several intermediate places upon the coast; but it chiefly occurs either below the water of the lake, or so little elevated above it as scarcely to be capable of being turned to any considerable practical account. Outer Thunder Bay island is composed of limestone, covered, in part, by a very thin deposite, chiefly of vegetable matter. An inferior coarse building stone may be obtained, in considerable quantities, upon this island, but it is extremely irregular in shape and not of the most durable character. The southerly portion of outer Thunder Bay island is composed of a shelly or sub-slaty, silicious limestone, considerably charged with bitumen, and almost wholly composed of a congeries of fossils, the animal matter of which has undoubtedly given rise to the bituminous character of the rock. It possesses much interest in a scientific point of view, but is of no value for any practical purposes.