the lake the present river has a course farther west than the preglacial course. The borings indicate that the deepest part of the preglacial valley runs nearly north from Willow, along or near East Fifty-fifth Street, to the shore of Lake Erie. In two places the rock is reported to be below sea level-one at the shore of Lake Erie west of Gordon Park and the other east of Independence, about 12 miles from the lake. The records of several borings that show remarkably thick drift and low altitude of the bedrock have been collected by Prof. J. E. Hyde, of Western Reserve University. These records indicate a lower altitude near the east side of the preglacial Cuyahoga opposite Independence than in the middle and western parts of the valley.

There are two borings opposite the mouth of the preglacial valley of Tinkers Creek, one of which shows a rock floor 20 feet below sea level and the other 4 feet above. Five borings within an area of about 40 acres about half a mile farther west, near the middle of the valley, strike rock at 45, 50, 130, 275, and 306 feet above sea level. The borings reaching bedrock at 45 and 50 feet are a little farther east than the others. Several borings west of the middle of the valley enter rock at levels between 300 and 400 feet above sea level. The deep excavation thus seems to be confined to the eastern half of the old valley and to a width of about half a mile. The east bluff, only half a mile north of the place where the rock floor is lowest, has rock up to 800 feet above sea level and a mile farther north up to 930 feet. The bluff is therefore remarkably steep for a preglacial valley formed by subaerial erosion.

A line of borings running from east to west across the city of Cleveland, reported by Upham,' shows a similar condition, as appears in the table below, slightly modified from the original.

Wells along or near Euclid and Detroit Avenues

With the two exceptions noted the wells are all about 100 feet above Lake Erie, so the deepest one recorded in the list strikes rock at 340 feet below the level of the lake, or 233 feet above sea level. There is, however, only one boring, that at East Seventy-first Street, within a distance of nine-tenths of a mile in the deep part of the valley. There is thus abundant room for a deeper channel about as wide as the deep one near Independence. Upham reported a boring north of this line, on ground only 50 feet above Lake Erie, that failed to reach rock at 520 feet, thus showing the rock surface there to be less than 100 feet above sea level.

Mr. H. A. Dempsey, a driller of Cleveland, reports a well drilled for the White Co., just southwest of Gordon Park, which reached rock at about sea level, or nearly the same as the level of the lowest bedrock surface near Independence. He also reports a well several miles to the south, just north of Forest City Park, which reached rock at about 40 feet above sea level. He argues from data that he possesses that there is a deep channel in the floor of the Cuyahoga Valley, cut down to or slightly below sea level and running from a point at least 15 miles south of the lake; and that the channel is narrow, its width being about a quarter of a mile. The data strongly suggest such a channel.

The Cuyahoga Valley is cut out of very weak shales, and before the discovery of this inner and narrow deep channel Cushing was disposed to maintain that the valley had been deepened by glacial action. This inner channel, however, would seem to be fatal to this view, as it must have been cut by a stream, and glacial deepening would have obliterated it, although if it had become filled with sand prior to the glacial advance, its narrowness would have prevented vigorous ice action along it. A certain amount of glacial erosion in the valley is definitely suggested by the nearly vertical attitude of the valley walls here and there, as at the mouth of the preglacial valley of Tinkers Creek, already described, and even more prominently on the east wall of the valley opposite Boston Mills, where there seems to be a nearly vertical rock wall at least 700 feet high. Borings along the Rocky River, although showing a channel cut about 200 feet below the level of Lake Erie, have not given evidence of excavation to a level corresponding to that on the Cuyahoga Valley. It is possible, however, that borings have not penetrated to bedrock in the deepest part of the preglacial Rocky River channel, for only a few borings have been made along its course. The valley of the preglacial Rocky River makes a gap more than a mile wide in the shale bluff where it enters Lake Erie, a short distance west of its present mouth, so that many borings are needed in order to test its depth fully.

The preglacial Rocky River is followed by the East Branch across Strongsville Township, but thence the preglacial channel runs northward through Middleburg Township, passing east of Berea and embracing the headwater part of Abram Creek. It crosses to the west side of the present stream directly west of Kamms and continues a short distance west of the river from that point to the lake. The gap in the shale bluff west of the mouth of the present stream was interpreted by Newberry as marking the channel of the preglacial Rocky River, but the course of the channel was first traced by Dr. D. T. Gould, of Berea, several years later.

CULTURE

These three quadrangles are situated in one of the most densely populated regions of North America. A large and rapidly growing city contains the greater part of the population; the city is closely adjoined by suburban towns and villages that are practically parts of it and one by one become incorporated with it; and the villages steadily expand into the surrounding rural territory. The rural areas also are evenly and densely populated. The exact population of the quadrangles can not be given, because they do not contain all of Cuyahoga County and do contain parts of Medina, Summit, and Lorain Counties. But as the part of Cuyahoga County that is not included in these quadrangles is roughly equivalent in area to the included parts of these other counties, as no large village is situated in either, and as the rural population is about equally dense in all, it seems reasonable to assume that the population of the quadrangles is the same as that of Cuyahoga County. This was in 1910, 637,425, or about 1,275 to the square mile; in 1920, 943,495, or 2,038 to the square mile; in 1930, 1,201,455, or 2,595 to the square mile.

The city of Cleveland in 1930 had a population of 900,429. Several immediately adjacent villages and towns are so closely grown to Cleveland that the community lines are obscure, although the civil distinctions remain. Bratenahl, East Cleveland, Euclid, South Euclid, Cleveland Heights, Shaker Heights, Garfield Heights, Newburg Heights, Lakewood, and Rocky River had in 1930 a population of 222,735. The Cleveland community, including these villages, together with thickly settled parts of adjacent townships, therefore probably has a total population of about 1,150,000.

The rural population is essentially agricultural. The Erie Plain is largely devoted to raising fruit, especially grapes. The whole dis trict is under cultivation except a few excessively steep slopes, a few small marshy tracts, and parts of the high-level Pottsville (Sharon) conglomerate outliers. Owing to the nearness of the large city, truck gardening is extensively carried on. Especially well adapted to this

purpose are the sandy surface of the Cleveland moraine in Brooklyn Township, the filled old valley of Rocky River, and the black-soil areas-formerly marsh accumulations-just south of the old lake beaches in the Berea quadrangle.

On the plateau wheat, corn, oats, and hay are the principal crops and some fruit is raised. Little forest remains in these quadrangles except in the narrow stream valleys and on the Sharon summits of the plateau. This forest consists chiefly of hardwoods, and there are many groves of sugar maple that supply a large run of sap in the early spring.

Cleveland is a large manufacturing center and has distribution both by lake and by rail. It is near an abundant supply of excellent coal and receives annually a huge tonnage of iron ore. A large proportion of each is used here, and the rest is transshipped. Manufacturing is far more diversified than in many other industrial centers. The city serves also as a distributing point for an extensive surrounding area. The quarry industry, of which both Berea and Euclid are or have been local centers, is large.

Two trunk-line railroads that follow the Erie Plain across Ohio, the New York Central and the New York, Chicago & St. Louis, pass through the quadrangles. Branch lines of the Pennsylvania, Baltimore & Ohio, and Erie Railroads run into Cleveland from the main lines of these systems, which cross the plateau on the south. The lines of the Big Four Route begin at Cleveland and run west and southwest, and the Wheeling & Lake Erie has a terminal here. The Belt Line Railroad encircles the city and connects all these railroads. Seven electric railroads radiate from the city, along the lake both east and west and to the southeast, south, and southwest, of which three have recently been considerably restricted in the length of their lines in operation.

Passenger steamers to Buffalo and to Detroit leave Cleveland daily in the navigation season. The through boats from Buffalo to the upper lakes all dock at the city. Lines also run to Sandusky and the islands and across the lake to Port Stanley. Freight steamers in great numbers ply the lake, loaded for the most part with iron ore, coal, or grain. This traffic is closed in winter.

The Ohio Canal, which formerly extended from Lake Erie to the Ohio River, passes up the Cuyahoga Valley from Cleveland. No use is made of it at present, except as a source of water supply by certain industries under lease from the State.

All parts of the quadrangles are reached by public roads, many of which are graveled, others are ordinary dirt roads, and some are of clay. Over the clay roads traffic is very difficult in wet weather. Practically all the chief highways are paved with brick, concrete, or asphalt, and the paving is constantly being extended.

2953-31- -3

The chief obstacles to railway and highway construction are the deep Cuyahoga and Rocky River Valleys and the escarpment. Through east-west traffic has the grades of the valley walls to overcome; that to the south must climb from the level of the plain to that of the plateau. The valleys must be crossed by long and costly highlevel bridges and viaducts, or else by steep grades. The New York Central Railroad crosses the Cuyahoga River at a low level (about 580 feet) near its mouth, and then swings far south to Berea, which is 200 feet higher, so as to cross the two branches of the Rocky River above the falls and gorge. Westbound trains from Cleveland therefore have a heavy grade to overcome. Eastward the rise is more gradual. The New York, Chicago & St. Louis Railroad crosses the Cuyahoga Valley farther south by a long, high trestle, and the Belt Line crosses by a still higher one. Most of the roads running southward have steep grades across the quadrangles. The Baltimore & Ohio Railroad runs up the Cuyahoga Valley with a lower grade than that of any other of these roads, but this grade is balanced in part by an exceedingly heavy grade where the road leaves the valley at Akron. The other railroads utilize small branch valleys. The Big Four goes up Walworth Rur the Erie up one branch of Kingsbury Run, the Wheeling & Lake Erie up Morgan Run, and the Pennsylvania follows in part the shallow valleys of Mill and Brandywine Creeks. In its 20-mile course across the Euclid and Cleveland quadrangles the Pennsylvania roadbed rises 420 feet, an average of 21 feet to the mile; this is a fair sample of the grades that must be overcome in passing from the Erie Plain to the Appalachian Plateaus, unless heavy construction is resorted to. The more recent Pittsburgh & Lake Erie Railroad, a unit of the New York Central system (not shown on the topographic map but following the east wall of the Cuyahoga Valley), by a series of great fills and bridges across the tributary valleys, accomplishes the ascent by a grade of about 15 feet to the mile over many miles in length.

STRATIGRAPHY

GENERAL FEATURES

By H. P. CUSHING

The exposed rocks of the three quadrangles are wholly of sedimen tary origin and range in age from late Devonian to Pleistocene. They fall into two general classes-indurated stratified rocks of late Devo nian and early Carboniferous age and unconsolidated surficial deposits of Pleistocene age. The Pleistocene deposits form a blanket of rela tively slight thickness over the surface of nearly the whole district. The indurated rocks everywhere underlie them and crop out in the beds and gorges of streams, in the escarpments, and in a few other places, and they have been exposed in numerous quarries and other excavations. (See pl. 20.)