The History of Genesee County, MI
Chapter VIII
Geologic Conditions of Settlement

Online Edition by Holice, Deb & Clayton




In its geological structure the county of Genesee presents a double aspect. The geologists of the state aptly call the first the "bed rock" geology. This is the bed rock basis upon which the other structure, consisting of glacial drift, is superimposed. If this covering of glacial materials could be removed and the basic rocks underlying be exposed in their contours, the landscape that would be presented would be of extreme interest. It is not at all easy to visualize this hidden formation that upholds the later deposits, but from the data that we have from drilling wells, from some shafts that have been sunk for purposes of coal explorations, and from excavations fro quarries and clay mining, we may get a glimpse of it.

Certain river beds and smaller drainage courses would be seen, and the general course of the principal one would be found meandering across the county from the southwest toward the northeast, and at this time but partially defined, as the drillings have not been sufficiently extensive to give all the desired data.

Outcropping the rocky banks of these courses would be found sandstone, of considerable thickness in places, interstratified with shales, thin veins of limestone an, rarely, very thin coal veins. In the bottom of these beds might also be found, exposed at intervals, coal veins of considerable thickness. The depth of this principal drainage bed has been determined at certain points to have been at least three hundred and twenty feet--in the northeastern part of the country.

It may be said that this river bed runs approximately across the towns of Argentine, Gaines, Mundy, curving eastward through Grand Blanc into Burton and toward thread Lake, crossing the city of Flint toward the hospital, thence northward toward Mt. Morris, turning then into Genesee township, and through that meandering toward Forest and through that town, where it reached its greatest depth.

This pre-glacial valley, which the oil drillers of Ohio would call the "lobe," had its lateral affluent valleys. To Henry Meida, an experienced well driller, whose work has extended through many of the towns of our county and who has been interested to keep records of other wells, we are indebted for these facts. From his statement the various depths of hard rock under the city of Flint are as follows: On the edge of Thread Lake and near Stanford avenue, 220 feet; on Nichols street, near Swartz creek, 20 feet; on Grand Traverse street, corner of court, 70 feet; on the corner of Beach and Ninth streets, 100 feet; on Fremont road east of G. T. tracks, about 56 feet; near M. S. D., 100 feet; a mile south of that, 150 feet; coal mine of Old Genesee Coal Company, 150 to 180 feet; corner of Detroit and Ninth avenue, 130 feet; near Crosby and Detroit streets, 200 feet. Away from the principal drainage course as given above, the depth in many places runs about twenty to thirty feet.

In general terms, the hard rock formation under our county maybe said to be of the Saginaw and Woodville formations, as classified by our State geologists, corresponding to the Conemaugh of Pennsylvania. It is of the upper coal measures and a part of the great central coal basin of lower Michigan, which comprises the counties of Shiawassee, Clinton, Ionia, Gratiot, Isabella, Montcalm, Midland, Saginaw, Bay, Genesee, and part of many adjoining counties. Saginaw in particular deserves special mention, as it is there and in Bay county adjoining, that this coal region referred to has been commercially developed. If we will bear in mind the mitten shape of our peninsula, this coal basin might be figuratively said to lay in the mittened hand.

Mr. Brentz, now of the geological department of Chicago University, when he was teacher of Flint High School made some geological explorations of the county. He states that the general surface of the underlying hard rock foundation of the county conformed generally tot he surface of the present time, suggesting that the distribution of glacial materials over this hard rock was rather uniform in thickness, or relatively so.

The present surface of our county, its physiographic features, the contour of its hills and valleys, however, are the results of a different and later geological period--the period of glacial action, when the ice fields that covered the greater part of northern United States hid this hard rock, filling in its drainage courses, its river beds that had been eroded through the action of water during the long geological ages, and made a new surface. The old things passed away and new condition reigned. The rugged rocky hills, that towered above these ancient valleys and ravines, with their caverns, and rivers running over rock and shingle, were hidden by the gravels, sand, till, clay and boulders tht were transported by the mighty force of the moving river of ice from the north, which flowed a few feet each year over our land, and finally, when that ice sheet receded under the heats of an altered climate, the receding glacier, halting its retreat here and there as though reluctant to give back the land that ws part of itself, here in mounds, there in ridges, damming the waters, or directing their courses, made a new land and prepared for a new life. The river that had been, ceased to be, and a new river was born, to run according to the will of the glacier that gave it being. The genius of the ice was not content to take a life, as in the poem of Goethe, but busied itself with making a continent.

When the receding glacier had so far retreated that the southern portion of the state was freed from the ice, the lobe that pushed itself up through the bay of Saginaw, lingered, and its various stages of recession and retrogression made the hills and valleys, guided the waters of our county, made the soils, piled up the gravels, spread the clay, the sand and gravels, and gave potential being to the deposits of marl in the lakes; then the county of Genesee was formed and its future was determined.

This lobe, the Saginaw glacier, spread out over the entire county. Its effects upon the drainage were especially interesting and here is perhaps the best example of what the geologists have termed the "willowy" system of drainage. If we will note the direction of the streams, that together are the drainage of the Saginaw valley in its extreme extent, we will see this system in its perfect development. Turn a map of Michigan over so that we face the head of the bay of Saginaw. Note the Saginaw river entering the head of the bay, to its head waters, and we see that the main river follows along a course that almost parallels the shores of the bay, curving around southwesterly, then west, then north by northwest, until it joins the Saginaw; then follow the course of the Tittabawassee, as it curves around parallel to the western shore of the bay, in a similar way, until it reached and joins its waters with those of the Saginaw and Cass, and all are discharged through the Saginaw into the bay. This system of drainage, from its similarity to the willow tree, gives the name "willowy" to the geological nomenclature of this day. the Saginaw river forms the trunk of the tree, the two rivers named form the drooping branches, and the other affluent streams, the tree top, and the striking similarity is apparent.

The question occurs, What is the cause of this peculiar drainage system? Why did not these rivers all flow direct toward the bay which finally received their waters? The explanation is the glacier. The waters of Genesee county furnish a less conspicuous example of the same kind of drainage and its course is also assignable to the same cause.

The sites of the two most southern townships of our county, Atlas and Fenton, were the first to emerge from the ice of the glacier. For a considerable period of time after their emergence the rest of the county continued to deposit its earthy materials along its edge, forming a distinct moraine across these two townships, and damming the waters that were along one edge, which, following the line of least resistance, toward the west, formed the Shiawassee river; its course is directed by moraines of the two townships. The emergence of these two townships from a field of ice meant their general submergence by the waters of the glacier. The lake formed by these waters still exist in the following: Copnaconiec, Long, Loon, Mud, Silver, Ryan, Pine Squaw, Lobdell, Shina, Mecastin, McKane and Myers, together with many unnamed ponds and kettle holes.

The Shiawassee river receives its tributaries from the south, except some of the lakes mentioned, which discharge their waters into that river. these two towns display the most striking evidences of glacial action; the names and ridges are marked, in many places, of considerable magnitude. There are few places better adapted to the study of glaciation than this portion of Genesee county, not even excepting the region of Green Bay, Wisconsin, nor the Leaf Hill of Minnesota.

Of the Shiawassee river, Mr. Bretz says: "But a few miles north the land lies lower than the level of the stream (Shiawassee). The river does not flow north seeking this lower level, because a moraine borders its northern side and the valley is occupies was first formed by border drainage from the ice sheet at the time the moraine was built. The actual surface of Genesee county at tht time was much higher north of the Shiawassee river, because the great ice sheet covered the land. As it melted, its waters ran along its edges through this part of the county, eroding a valley, which the present Shiawassee now occupies, though a puny successor to the glacial streams."

A further recession of the Saginaw glacier, and a temporary stand of its field of ice is marked by a line running through the townships of Forest, Richfield, Genesee, Flint (city and town), the corner of Clayton, and perhaps Gaines. This stand is evidenced by morainic deposits along the northern bank of the Flint river and the Swartz creek. This moraine holding back the waters, and the glacier itself, forming an extensive lake covering the greater portion of Burton, Mundy, Grand Blanc, Davison and Richfield. And this lake finally, after the glacier had further receded, found an outlet through the great moraine where the city of Flint now stands and in the fifth and third wards, forming the Flint river as the trunk of the willow, which with the upper Flint river, the Swartz creek, the thread river, the Kearsley creek and the smaller streams, make up our local willowy drainage. This drainage basin is made up of gently sloping general surfaces, all tending toward the eroded outlet of the ancient lake at Flint, and coming from the east rather than from the west, as the general slope of the county towards the northwest would lessen the drainage from the west. The Swartz creek, because of these facts, furnishes the smaller contribution to the waters of the outlet, the Flint below the city, than the other side of the willow tree.

To quote Mr. Bretz again, "Thus, practically the whole drainage of the southern half of Genesee county, excepting the Shiawassee river, comes to one point where the Flint river cuts through this moraine in the west part of the city of Flint. North of this barrier, the Flint moraine, the streams again take the consequent course with minor deflections. Since the surface is more or less irregular with small moraine ridges, and the beaches of a second glacial lake, the adherence to a strictly consequent course if not marked"

This covering of the basic rock formation by the glacial detritus, belongs to the pleistocene period. In this drift maybe found the rounded boulders from the granite rocks of the far north, the sand and gravels, decomposed remains of the sandstones, clays of various kinds, in which the blue clay predominates, and which, in some of the power portions, assumes a semi-stratified appearance.

The materials of this period have been of great importance in the economic development of the county. The absence of exposures of stratified rocks made the quarrying of stone impossible except in the township of flushing and along the lower stretches of the river; the boulders entered into the building of the foundation of the early homes of the city and rural portions of the county. Sand of suitable quality for building purposes is found in nearly every town. In many places it was not uncommon to find sand in the excavation for the foundation, of suitable grade to make mortar for the walls. Gravel for road-making was also common as a part of the glacial materials. In 1913 there were thirty-three dealers in sand and gravel for commercial purposes in the county of Genesee; the townships of Atlas, Burton, Davison, Fenton, Flint, Flushing, Gaines, Genesee, Mundy, Richfield and Vienna were all represented in the list.

The lakes of the southwest part of the county contain marl of a high degree of purity and great commercial value. The deposit is both rich and of great depth. In the early days the settlers used it to a limited extent for burning lime, and it entered into the building of foundations and the plastering of house of settlers. The lime used in the early building activities of the city of Flint came for the most part from similar marl deposits in similar glacial lakes of Lapeer county near the line of Genesee. Of these, Lime lake furnished perhaps most. This marl was also used by the housewives for scouring materials.

Transported boulders of limestone sometimes occurred of sufficient size and frequency to use for lime burning. One instance of this was an especially large boulder of that stone on section 7, township 9, range 8, east, Forest township.


History of Genesee County, Michigan, Her People, Industries and Institutions
by Edwin O. Wood, LL.D, President Michigan Historical Commission, 1916

Transcribed by Holice B. Young

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