time the junction of the East and West Branches was north of two rock prominences north of the road running east from Olmsted. The channel west of these prominences, about 100 feet deep, was probably cut by the West Branch and later abandoned. The diversion through the gap at the road east of Olmsted is said to have occurred at about the time the first settlers came to this region. The diversion through the passage between the rock prominences was evidently much earlier. The erosion on tributaries of the Cuyahoga and Rocky Rivers has been relatively slight, except in the lower courses, where they are coming into adjustment with the deep valleys of the major streams. There are usually cascades where the streams pass from sandstone to shale formations. Such cascades are conspicuous where the streams pass out of the Berea sandstone. Excavation in the rock formations has been very slight except as stated above. The drainage of the elevated upland is to a great degree rudely coincident with the preglacial lines, but on the lowlands the preglacial drainage channels have been so completely filled with drift deposits that most of the present streams follow new courses.

ECONOMIC GEOLOGY

By FRANK ROBERTSON VAN HORN

The mineral resources of the Cleveland, Berea, and Euclid quadrangles consist of clay and shale, building stone and grindstones, salt, natural gas and petroleum, sand and gravel, and road material. These substances are named in the probable order of their commercial value. Other natural resources are peat, water, and the soils.

CLAY AND SHALE

The clay industry in Cleveland and vicinity includes the manufacture of common brick; vitrified brick, which embraces face brick, sewer brick, and paving block; and hollow ware, such as hollow brick, fireproofing, conduits, and a small quantity of drain tile.

Clay. The clays of the region are chiefly transported material of glacial origin. They are either yellow or blue, and the beds range in thickness from 3 to 75 feet. In one place, however, borings indicate a thickness of more than 150 feet. The blue clays are very dense and tough, and dynamite is sometimes employed in mining them. Boulders usually occur in the clays but in places are practically absent. They consist of granite, gabbro, anorthosite, gneiss, schist, and several kinds of limestone. The limestone is especially detrimental in brickmaking, as on burning any particles present are converted into lime, which will absorb moisture and cause the brick to chip off or even break into pieces. Some alluvial clay is found along the streams, but

none is used for manufacturing. The nearest approach to a residual clay in the region is the so-called DeKalb clay,13 found in a strip a quarter of a mile to a mile wide and parallel to the shore of Lake Eriefrom Dover Bay through Lakewood and Nottingham toward Wickliffe. It has been formed largely by the weathering of the Chagrin shale, although probably added to by wave action when Lake Erie stood at a higher level. An ultimate chemical analysis of this clay and of one of the common blue clays called "Erie clay" by Newberry follow:

Analyses of clays from the vicinity of Cleveland

1. DeKalb clay (residual) from John Kline Brick Co., Wickliffe, Ohio. Analysts, F. J. Peck & Co. 2. "Erie" clay, a blue drift clay used by some of the brickmakers of this vicinity. Ohio Geol. Survey, vol. 1, p. 177, 1873. Analyst, T. G. Wormley.

Comparison of analysis 1 with that of the Chagrin shale (No. 3, p.106) shows a great similarity save for the increase of silica in the clay, which might be expected. The DeKalb clay shows a slight loss of soluble constituents-alkalies, lime, magnesia, and iron. It is utilized only incidentally as it falls into the pit of Chagrin shale, which is used at Wickliffe for the manufacture of vitrified brick and paving block. If, however, the clay were present in sufficient quantity, it could be used for brickmaking, for which it is well adapted. The sulphur shown in the analysis comes from undecomposed pyrite concretions in the shale. Analysis 2 shows a large percentage of magnesia and lime, which probably originate in part from the limestone pebbles that generally occur in the drift.

Shale. The shales of the region that are utilized for clay products are the Chagrin, Cleveland, Bedford, and Orangeville. The Chagrin shale is predominantly grayish blue; the Cleveland shale is commonly black, although some layers are dark blue; the Bedford shale is part red and part blue; and the Orangeville shale is near black, although usually not so dark as the Cleveland. Most of the shales contain concretions of pyrite, and in some beds of the Chagrin clay-ironstone

1 Lapham, J. E., and Mooney, C. M., Soil survey of the Cleveland area, Ohio, p. 19, U. S. Dept. Agr. Bur. Soils, 1906.

2953-31-8

concretions are very abundant. Several ultimate analyses of the shales were obtained from the brick companies and are given below. Analyses of shales from the vicinity of Cleveland

1, 2. Chagrin shale, blue, Cleveland Brick & Clay Co. F. J. Peck & Co., analysts. 3. Chagrin shale, blue, John Kline Brick Co. F. J. Peck & Co., analysts.

4. Chagrin shale, brown, Newburg Brick & Clay Co. F. J. Peck & Co., analysts.

5, 6. Chagrin shale, blue, Newburg Brick & Clay Co. F. J. Peck & Co., analysts.

7. Chagrin shale, blue, Ohio Clay Co. Oscar Textor, analyst.

8. Cleveland shale, black, Cleveland Brick & Clay Co. Oscar Textor, analyst.

9, 10. Cleveland shale, black, Cleveland Brick & Clay Co. F. J. Peck & Co., analysts.

11, 12. Cleveland shale, black, Brower farm, Ohio Clay Co. Oscar Textor, analyst.

13. Cleveland shale, black, Newburg Brick & Clay Co. F. J. Peck & Co., analysts.

14. Green repressed paving block of the Cleveland Brick & Clay Co., made from Chagrin and Cleveland shales with very little glacial drift. F. J. Peck & Co., analysts.

15. Green repressed paving block of the Newburg Brick & Clay Co., made from Chagrin shale with a little Cleveland shale but more glacial drift. F. J. Peck & Co., analysts.

16. Average of seven samples taken in proportion to the thickness of strata from the side of a cliff consisting of Chagrin and Cleveland shales with glacial drift. Analyses made for the Ohio Clay Co. Oscar Textor, analyst.

17. Bedford shale, northern Ohio, presumably from South Park or Independence, Cuyahoga County. (Ohio Geol. Survey, vol. 7, pp. 133-134, 1893. Analyst not stated.)

18. Bedford shale, northern Ohio; same as 17 but different sample and analyst.

19. Average of 10 samples of shales, chiefly of Carboniferous age, used for making vitrified brick, block, and sewer pipe elsewhere than in the Cleveland district. (Ohio Geol. Survey, vol. 7, pp. 133–134, 1893.)

The analyses given above were made for commercial work, and the determination of certain substances only was asked for, which accounts for the fact that several constituents were not determined and that very few analyses have a total of 100 per cent. In analysis 3 the water was determined by ignition with a deduction for the sulphur, and in analyses 7, 8, 11, 12, and 16 a similar calculation was made for the carbon. Comparison of the several analyses shows a marked similarity in the composition of the three shales (Cleveland, Chagrin, and Bedford) used most in the region for brickmaking, although they are of different geologic age. This similarity, however,

is to be expected, as shale represents a definite product from a definite series of geologic processes, just as sandstone does.

The silica, alumina, magnesia, and lime tend to be slightly higher in the Chagrin shale than in the Cleveland. The Cleveland is always immediately recognized by the amount of carbon present. The percentage of iron seems to be somewhat higher in the Bedford, and this might be expected because this shale is generally red. The constant amount of sulphur trioxide (SO3) is due to the presence of pyrite (FeS2). In analyses 7, 8, 11, 12, and 16 sulphur was certainly present and has been included with water as driven off by ignition. Analysis 19 indicates that the shales of the district conform closely to the composition of other shales used in Ohio for the same purpose. Analyses 14 and 15 show the exact composition of the mixture used in a shale brick. Analysis 14 shows by the amount of carbon present that less than 20 per cent of Cleveland shale must have been used. In the shale bank of the Cleveland Brick & Clay Co. about 3 feet of glacial drift overlies 2 to 3 feet of blue Bedford shale, beneath which is 18 to 20 feet of Cleveland shale and about 88 feet of Chagrin shale. The section used for making the brick analyzed in No. 15 consists approximately of 16 feet of drift clay, 6 feet of Cleveland shale and 113 feet of Chagrin shale. The glacial clay undoubtedly contained some quartz sand, which made it richer in silica than any of the shales. In fact, there are many gradations from clay to sand and the reverse in all the glacial deposits of the region. The 6 feet of Cleveland shale, however, was not sufficient to make any impression on the analysis, if the carbon content is taken as an indication.

BUILDING STONE

The quarry rocks of the Cleveland district are only two-the "Euclid bluestone" and the Berea sandstone or "grit," as it is generally called.

"Euclid bluestone."-In the immediate vicinity of Cleveland the lowermost part of the Bedford shale is replaced by a lenticular mass of bluish-gray argillaceous sandstone which was named by Prosser the Euclid sandstone lentil. This sandstone has long been quarried under the name "Euclid bluestone." It ranges in thickness in the quarries from 20 to 30 feet, is dense and fine grained, and is much harder, stronger, and less friable than its better-known neighbor, the Berea sandstone. In general it is thinly and evenly bedded, and on that account it was at first and to a small extent is yet used for flagstone without being sawed. In one locality about 20 layers were noticed in a thickness of approximately 15 feet, and many of them ranged from 2 to 6 inches thick. The specific gravity of one specimen was found to be 2.583, hence the stone weighs about 160 pounds to the cubic foot.

The only quarries worked much are at Newburg in the Cleveland quadrangle, and at South Euclid, in the Euclid quadrangle. At Newburg are two layers having a thickness of 34 feet each; at South Euclid the layers reach a thickness of 5 feet. In places the bluestone contains concretions in which is a great deal of pyrite. They seem denser and harder than the surrounding rocks and are a source of detriment to the stone which becomes stained yellow or brown by the oxidation of the iron sulphide to ferrous sulphate and finally to limonite. Some of the freshly quarried stone shows no trace of the concretions, but on exposure to the weather for several months the structure becomes visible. The "Euclid bluestone" is used chiefly for flagging, but it is also largely sawed for caps, sills, and steps. Perch stone is also furnished for cellar blocks and foundations. It is reported that this stone is used for making laundry tubs after it is treated chemically to decrease absorption. A considerable quantity is crushed for concrete work, the finer screenings being employed for concrete block and mortar sand. To a small extent the stone is used in making drives and roads.

Most of the following analyses of the "Euclid bluestone" are only partial, because only certain determinations were demanded.

Analyses of “Euclid bluestone" near Cleveland

1. Light bluish gray, Malone quarry No. 2, South Euclid. Collected by Frank R. Van Horn. Analysis made for Ohio Geological Survey in 1909 by Prof. N. W. Lord.

2. South Euclid. Analyzed by Edward Orton, sr., former State geologist.

3. South Euclid. William Pate, jr., analyst.

4-7. Light yellow, Burgess quarry, South Euclid. William Pate, jr., analyst.

The analyses show a considerable range in silica, alumina, and iron. In analysis 1, which is the most recent, the alkalies were not determined. This analysis likewise shows that most of the iron is in a ferrous state in the unaltered rock. The change to a ferric state is shown in analyses 5, 6, and 7, where the rock was stained yellow.

In addition to the crushing resistance given with the preceding analyses, the following results were obtained on "Euclid bluestone" from the quarry of the Caine Stone Co., Newburg, by H. D. Pallister at the Case School of Applied Science. The specimens were approximately 3-inch cubes.