conglomerates. This is a phenomenon of depth solely, and is apparently found only where the beds are at least 30 or 40 feet below the surface. However, by no means all of the gravels at these or greater depths are cemented, in fact cementation appears to be rather exceptional.

Bed rock formations.-At several localities small areas of the bed rock come to the surface and even form low hills above it. Their location can be seen from the accompanying geological map. These are entirely of Cuyahoga shale, a rather soft, clay shale, with enough thin sandstone that the debris of the latter is prominent.

Probably the Cuyahoga shale lies but a short distance below the surface in many places. It probably forms the backbone of the point between Walnut and Little Walnut creeks, and again between Little Walnut and Dry Run.

The maximum depth of the gravels is unknown. Between Lick Run and the Scioto River, it certainly attains 140 feet with no rock, as shown by the ravines which dissect the upper terrace. No wells so far as they are known have approached this depth, though they commonly penetrate 60 or even 100 feet.

WATER

Streams. This is one of the most abundantly watered subdivisions of the quadrangle. Besides the permanent streams mentioned above, Lick Run, Dry Run, Walnut and Salt creeks, there are numerous small streams which are fed by unfailing springs. There are peculiarities in behavior. For example, the small ravine with the lane in Section 27, Springfield Township, is dry except after rains, while the next one to the northwest has a heavy permanent flow of water from springs. In this case the first mentioned has much more sand poured into the stream, perhaps because of a difference in the amount of dissection and the character of the farming, and the flow of water is below these sands. The one to the northwestward has no such sand filling in its channel and is in the first deeply cut valley south of the rock hills.

Ground water. Springs are abundant, and many of them are remarkably strong. Wherever valleys or large gullies have been cut well below the surface of either the middle or upper terrace, springs are apt to be present near the foot of the valley slopes. Since no such valleys are cut in the lowest or Wisconsin terraces, they are not present to such an extent there. The gravel and sand composition of the terraces is the cause for the absorption and storage of a large proportion of the water falling on the subdivision. This finds its way out at the foot of slopes bordering the deeper stream valleys unless, as is common, there are beds of clay in the sands which cause the water to emerge higher. There are many springs which are located 10 or 20 feet up the slopes for this reason.

On the highest terrace, that is, with surface at 800 to 860 feet, wells are commonly sunk 60 to 80 feet to obtain water, but a good supply is almost always the result.

On the middle terrace, water is obtained at considerably less depths, from 15 to 25 or 35 feet, the last two being the more usual figures.

CONDITIONS AFFECTING EXCAVATIONS

All ordinary trench excavations on the surface of the highest and middle terraces will be in a reddish or yellowish loamy pebbly clay, not, it is believed, tough to dig. Probably at no place on the original upland surface will true gravels be encountered, but where excavations are made in much dissected portions, they may be met. The excavations will be dry at all seasons, except for the moisture from immediate rains, and will fall in rapidly unless protected. The clay-soil coat is commonly 10 or 12 feet thick. In the places where Cuyahoga shale is indicated on the accompanying geological map, excavation will be in clay shale with thin tough sandstones. Troops cannot be expected to dig in with intrenching tools on these last areas, unless much more time is allowed.

Excavations made on the slopes of stream valleys are certain to encounter these clay soils in much less thickness, and sands, gravels, and tough sticky blue clays very difficult to dig are almost certain to be met. In every case these gravels and sands are not of the sort to cave badly, though excavations should be protected against it. The cemented gravels, which occasionally are found on the lower slopes, will yield with difficulty only to the pick, and should be avoided. Trouble may be anticipated from water on all lower slopes, and judgment must be used.

Excavations in the two lower terraces and valley bottoms will encounter far less soil, and probably at most places will meet the gravels at less than 3 feet. The gravels at the surface are not at all consolidated and will cave quickly. Water may be encountered anywhere below 15 feet.

There are interbedded in the gravels of the middle terrace, beds of lake clay, tough, wet, sticky. The pick may be easily driven into this, and can then be extracted only with patience and at the cost of loosened and possibly broken pick handles. Though exceedingly difficult to excavate, these will, as long as wet, flow and cave slowly and excavation in these clays, or under them, should be avoided if possible. It is improbable that they will be encountered in rifle trenches anywhere on the uplands, though in any excavation beyond 15 feet they are apt to be met. On the slopes of the small valleys which dissect the terraces, they are certain to be met in the central and eastern portions of the subdivision; they are practically absent from the hills along the Scioto River.

As long as tunnels in the middle terrace are kept to the gravels and beds with considerable residual clay content, their excavation is the usual problem of gravels, somewhat lightened by a slight cementation; excavation will be easy and maintenance of the tunnel a matter of timbering. But if tunneling is attempted in connection with any of the beds of lake clay, special problems must be met. It is exceedingly difficult to dig, and creeps slowly under slight load.

Tunneling in the lower Wisconsin terraces bordering the Scioto will encounter only sands and gravels, unconsolidated except in a few places.

Depths at which water-bearing gravels may be expected are indicated approximately by the depths to ground water given above, but will fluctuate with the seasons.

MATERIALS FOR CONSTRUCTION

Stone. No stone suitable for construction exists in the subdivision. Gravel. The Wisconsin gravels in the terraces next the Scioto River are the best available supply. They are excellent for road material, but not wholly satisfactory for concrete because of the fragments of Ohio shale in them. A large pit has been opened by the Baltimore & Ohio Railroad just west of Dry Run. In certain layers there are large slabs of Ohio shale which are too much decayed and too fragile to be successfully eliminated in whole from the product. In addition there is much small material of the same sort scattered through it. The result, when used for concrete, may be seen in near-by Baltimore & Ohio Railroad concrete bridge abutments, of which the surface is pitted with scattered holes up to 1 or 2 inches in diameter where shale fragments have weathered out. The output could undoubtedly be much improved by washing.

An old pit at Peppers, on the south line of the quadrangle, was too badly tumbled in for satisfactory examination, but the gravel appears to be unusually free of shale fragments.

On the whole, the older gravels of the middle and upper terraces may be regarded as unavailable for concrete material. They are frequently high in sandstone pebbles, usually in clay, and are apt to have their pebbles and grains coated with limonitic dust. In places, however, poor outcrops have been seen of beds that promise an excellent quality of gravel if the clay content is not too high. These were particularly noted in the railroad cut 1 mile northwest of Schooley. It is possible that the overlying cover of sands, clays, and soils would prohibit the working of the gravel even if it proved satisfactory. It is free of shale pebbles and low in sandstone.

Creek gravels are poor in every case. All are too high in sandstone, some of them estimated 75 per cent, and Lick Run gravel is very high in black shale fragments. The sandstone fragments, more

over, were derived chiefly from the Logan and Coal Measures sandstones which are particularly weak in small fragments.

Sand. The only large source of sand, requiring no screening, which has been noted, is in the Wisconsin terrace of this subdivision, one-fourth mile south of the Main Street Scioto River bridge, where pits may be opened, and in the bed of the streamlet flowing through the center of Section 27, Springfield Township.

FORESTS

There are no extensive patches of forest. Such forest cover as remains is chiefly controlled by the topography; over the steep sides of ravines and gullies and their narrow bottoms small trees have frequently been left standing and very commonly such slopes are badly grown up with underbrush. This is especially likely to be the case in the ravines of the highest terraces. Of the rectangular wood-los of 10 to 20 acres, which are numerous in the northern third of the quadrangle, practically none remain. The flat lands of the middle and lower terraces are essentially clear of forest.

TRANSPORTATION

Transportation routes are fundamentally radial from Chillicothe. In the northern half of the triangular portion they are chiefly eastwest in direction, where they pass around the southwestern end of the knobs, shifting to northerly to serve the valleys of the Walnut creeks. In the broad, abandoned valley and along the Scioto, it is northwest-southeasterly in response to these natural courses of travel. The Richmondale Pike, which follows the Scioto Valley, is ample for two columns, but the Londonderry and particularly the Adelphi Pike are narrow in places.

Transportation in the north-south direction is more restricted. The routes are lacking in continuity and the roads are poorer.

A single change only need be noted, but an important one. Onehalf the length of the short road at the mouth of Lick Run, which connects the Adelphi and Richmondale pikes, was washed away by the 1913 flood, and has never been reconstructed.