Entered Trenton 144 feet securing oil and gas in small quantities, both of which disappeared and no more water was secured. Total depth of well 2277 feet.

§ 9. Interpretation of records.

In addition to the 200 feet which comprise the upper part of the Monroe series and which are exposed in various parts of the county, there are about 700 feet in the vicinity of Monroe which are known only through these deep well records. As stated in previous sections the thickness is less towards the Ohio line and increases northward. These beds consist of variously colored dolomites, some carrying considerable quantities of anhydrite. At 390 and 450 feet of the Monroe section the dolomite contains some shale, which is very probably the horizon of the "Tymochtee Slate," of N. H. Winchell. This was described and named in the geology of Wyandot county.* In his report of 1893,† Orton calls attention to this bed as one of the few recognizable horizons in the Ohio scale and states that it occurs below the middle of the series and probably within one hundred to two hundred feet of the base. At Monroe the bed itself has thickened from the twenty-four feet found in the typical Ohio locality and its lower layers lie from two hundred to two hundred and fifty feet from the base of the series. The shale reported in the Ida well at a depth of 320 feet is too high up for the Tymochtee and seems to correspond with those shaly beds which comprise the upper part of the Monroe section.

Beneath the Monroe beds in southeastern Michigan there lies a compact, rather homogeneous mass of dolomitic limestone known as the Niagara or Guelph. This is typically fine grained, very light colored and free from anhydrite and salt, apparently formed in the open sea before the concentration of the sea-waters had begun which characterized the succeeding age. The Monroe section shows about 360 feet of this formation, which near its middle portion becomes arenaceous. In Ohio the lowest member of the Niagara is a light colored shale, with thin calcareous bands. In the Wyandotte well ten feet of "slate" are regarded by Lane as the equivalent of the Niagara (Rochester) shale. Below the Niagara lies a bed of green'ish and reddish shale, about one hundred feet in thickness, to be referred to the Medina of the New York series. These colored

*Survey of Ohio, Vol. I, 1873, page 633.

+Survey of Ohio, Vol. VII, page 16. Geol Sur. of Mich., Vol. V, Pl. LXVI,

shales pass into the bluish Hudson River (Lorraine) calcareous shales which show a thickness in the Monroe section of 400 feet. In southern Ohio the Hudson River consists of alternating layers of blue limestone and blue shale. Northward the amount of limestone diminishes so that it is all liable to be classed as shale in well records. According to Orton it also grows darker in color and difficult to separate from the underlying Utica. Towards the Ohio line the thickness becomes less, reaching in northwestern Ohio 300 feet. The Utica consists of a mass of brown bituminous shale, becoming black towards its base. Its thickness seems to be about 160 feet beneath Monroe. Part of the 300 feet assigned to the Utica in the correlation of the Dundee well belongs to the Hudson. Finally comes the coveted Trenton, the deepest bed yet reached by the drill in this portion of the state. At Toledo the top of the formation is struck at about 812 feet below mean tide level. In the Potter well near Vienna its elevation is 978 feet below tide. In the three Monroe wells the Trenton was found to be lower toward the west or northwest. In the Moore well, third ward, the elevation is-1154 feet; in the Long well, 2d ward, it is -1149 and at the brick yard in the west part of the city it was found to be -1160. The average of these three gives-1154 feet. In the Dundee well the elevation was stated to be 1452 feet and -1490 in the Nogard well. These data give a drop in the Trenton from Toledo to Monroe of seventeen feet to the mile and from Monroe towards Dundee of about 26 feet per mile. These beds are all known in outcrop to the south, in Ohio, and northward about the shores of lakes Michigan and Huron. In southern Ohio the Trenton consists of heavy beds of true limestone with interstratifications of shale. Towards the north the shale becomes less and the rock passes into a true buff colored dolomite in which condition it enters Michigan. From the general dip of the Trenton it is apparent that Monroe county is located on the western slope of the great Cincinnati anticline.

This bed has long been known as the "Christiancy quarry," from the early owner, Judge I. P. Christiancy, formerly of Monroe. It is now owned by B. E. Bullock, of Toledo, Ohio. It is located in the former bed of the Macon River, from which the water has been deflected by an embankment, and extends for a distance of about thirty rods along the stream, with a main excavation of 450 by 200 feet. This is the most promising locality in the county for a high grade limestone, since the same beds are here exposed as at the now famous Sibley quarry, near Trenton. The quarry lies two miles northeast of Dundee, one-eighth mile from the Detroit and Lima Northern R. R. and three-fourths of a mile from the Ann Arbor Railroad. The nearness of the Macon interferes now with the quarrying of the deeper and heavier beds, but with an extension of the quarry northward, in which direction the stripping increases only slowly, the annoyance caused from the water would be gradually diminished. At present the water is pumped from the deeper portions of the quarry and drains slowly into the abandoned Nogard well. It thus seems likely that the deepening of the quarry will open up subterranean passages through which the quarry may be perfectly drained.

Four beds may be recognized in the quarry which may be designated as A, B, C and D in descending order. Bed A, the uppermost, consists of a rich, gray limestone from one to two feet in thickness, abounding in fossils. The limestone is relatively soft, glistens with cleavage faces of calcite and is thin bedded and more or less shattered. In the eastern portion of the quarry the top ledge of this bed has an elevation of about 660 feet above sea level. The second, or bed B, has a thickness of 4 to 4 feet and in places is nearly or quite without a seam. In other portions of the quarry it is divided into

thick beds. The rock is a compact, brownish limestone which assumes a bluish gray color on weathered surfaces. Fossils large enough to be seen with the naked eye are not as abundant as in the overlying bed and the cleavage faces are smaller. The rock gives a strong bituminous odor and drops of oil are occasionally seen in fresh specimens. With dilute hydrochloric acid a brisk effervescence is always obtained when the cold acid is applied to the solid rock. Toward the bottom the bed becomes somewhat cherty and in places there is interposed between this bed and the underlying bed C a seam of impure chert, varying in thickness from one to two inches. At the same horizon there is also to be seen in places a one inch seam of blue clay, more or less charged with sand. The main excavation of the quarry has taken place in these two beds but two deeper ones have been penetrated and their characteristics determined. Bed C has a thickness of seven to eight feet, is a soft limestone of a dark gray color, either without seam or very heavily bedded. Beneath this lies a somewhat similar eight foot bed, which the analysis shows is richer in calcium carbonate. The following table shows the chemical composition of these four beds, as determined by Mr. G. A. Kirschmeier, of Toledo.

Mr. K. J. Sundstrom, of Trenton, General Manager of the Sibley quarry and chemist for Church and Company, has analyzed specimens of the two upper beds with the following results:

From a careful study of the beds of the Sibley quarry it has seemed reasonably certain that the Macon beds are the equivalent of the deeper and better beds of that quarry. The analysis of the cores from the two test holes in the Sibley shows that their wonderful "9 foot bed" is from forty to fifty feet above the base of the series. The record of the Nogard well (Ch. III, § 8) shows at a depth of fifty-nine feet, a change from gray to buff limestone which probably marks the change from limestone to dolomite. If this is the correct interpretation, and there is much confirmatory evidence, bed D of the Macon quarry extends from thirty-eight to forty-six feet above the base of the Dundee formation. The actual difference in elevation between the top ledges of bed D and the "9 foot bed" is eighteen feet, this representing the amount of drop towards Trenton in the direction of the strike.

$ 2. Dundee quarry.

This consists of a rectangular excavation about 240 by 90 feet, upon the north bank of the Raisin, just back of the National Hotel in the village of Dundee. It is but a few feet from the water's edge, and as it is worked only in the late fall, was full of water at the time of each of several visits. Most of the information concerning the beds was obtained from Mr. Horace Pulver, the present owner, supplemented with a study of the blocks of stone piled about the quarry. The uppermost, or layer A, is two and one-half feet thick and consists of a rich, gray limestone, impregnated with oil and full of fossils. Fresh specimens are somewhat darker in color than those from bed A on the Macon, which it otherwise much resembles. Bed B is four and one-half feet thick and consists of a grayish brown limestone which gives a bluish effect on weathering. It shows but few fossils and is apparently identical with bed B on the Macon. The upper fifteen inches is said to be irregularly clouded and "gnarled." A third bed has been penetrated and found to be six and one-half feet thick. It is dark brown and bituminous and in the lower twelve to fifteen inches becomes cherty. Beneath this occurs a discontinuous seam of chert, carrying silicified fossils. It is of a light gray color, with brown streaks and is impregnated with black oil. It is very probable that this chert marks the same horizon as the similar seam in the Macon quarry and hence that bed B there is the equivalent of bed C in this quarry. Beneath the chert there occurs a heavily bedded five foot bluish layer, bed D, which