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the level Chicago Lake plain near Homewood, Ill., going on to the rolling Valparaiso moraine. The surface of the glaciated region traversed is for the most part rather level, but relieved in places, however, by heterogeneously distributed hills, and dotted with swamps and ponds. Boulders are scattered aimlessly about, and the railroad and river cuts expose the clays, sands, and gravels which compose the drifts. The kind and condition of crops also told the story of the nature of soil.

Underground water.-The work of underground water, which, by reason of its concealment, is always surrounded with a certain mystery and fascination, reveals its "black arts" in the limestone region of southern Indiana, Kentucky, and the "Great Valley" in Virginia just west of the Blue Ridge Mountains. We stopped at Louisville, Ky., to study at close range the interesting depressions in the surface of the country known as "sink holes." In Cave Hill Cemetery, Louisville, are fine illustrations of this type of the work of underground water. When the rock has been dissolved until the roof of a cavern becomes too weak to support itself, it collapses, leaving these depressions in the surface. Sink holes are sometimes very shallow, and look like huge saucers; again, they may be elliptical in shape, while their depth may be measured in inches or in hundreds of feet. These pits or depressions are frequently filled with water, making ponds and lakes in regions whose surface drainage is otherwise well developed. Throughout the Blue Grass region and the "Great Valley" the eye becomes skilled in recognizing "sink hole" landscapes. At Luray Cave in the Shenandoah valley, about fifty-five miles southwest of Harper's Ferry, are very striking results of this wonderful agent. In these caverns are displayed the most beautiful formations of stalactites and stalagmites, rivaling exquisite tapestry in design and color. These remarkable deposits certainly suggest power no less than magic.

While the caverns of Luray are among the most beautiful of their kind, they are not more interesting to the student of the work of underground water than the region about Natural Bridge, Virginia. Not only the celebrated bridge, but also the caves, sink holes, calcareous deposits, and roaring "Lost River"

all bear unmistakable evidence of the solubility of limestone. An interesting deposit of calcareous tufa, or travertine, may be found along the road about half-way between the famous bridge and Natural Bridge Station, three miles distant. The little stream flowing parallel to the highway is overcharged with calcareous matter which is precipitated in a beautiful terraced mound resembling, in form at least, that of the Mammoth Hot Spring in the Yellowstone Park.

Surface streams.-The work of running water upon the surface of the land is no less wonderful than that of underground water in its degrading and aggrading power; but its results are always before us, and hence become so familiar that they cease to stimulate the imagination, unless the grandeur of the scenery arrests the attention. In passing through the cañon of the New River from Kanawha Falls to Glades, W. Va., the Iron Gate near Clifton Forge, the cañon of the James at Balcony Falls, and through the gorge in Blue Ridge at Harper's Ferry, the aesthetic emotions frequently crowd out intellectual calculations, and it is not until the milder and more familiar type of landscape is reached that the meaning begins to be realized.

The description of the various results of the work of surface streams cannot here be given, but of the work of surface streams there is no form of wearing or building possible to rivers that is not well illustrated in some part of the region under consideration. There are valleys in every stage of erosive history, from the narrowest steep-sided gorge to the wide, level-bottomed, flood-plain; falls, terraces, islands, deltas, abandoned valleys, drowned valleys, with all the phenomena these terms imply.

Cultured influence of rivers.-The cultural influence resulting from the work of running water could not be overlooked. The magnetic attraction for railroads exercised by valleys was everywhere noted. From Ashland, Ky., to Richmond, Va., a distance of 373 miles, one is seldom out of sight of water. The distance of about twenty miles between Huntington, W. Va., and Scary, where the wide Teay Valley is traversed, must be excepted. This depression is believed to be the abandoned valley

of the Kanawha River, but now only the insignificant Mud River flows through it for a part of its course.

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When the Kanawha occupied this valley it is probable that the Ohio River did not exist, but that the Kanawha ran almost due west from just below St. Albans, instead of northwest as at present. It continued through the present Scioto River, and discharged toward the north. The subsequent ponding, during the glacial period, of the north-flowing rivers gave birth to the Ohio. The effect of falls upon the human history was noted at many places. The falls or rapids in the Ohio River at Louisville were almost obliterated at the time of our visit by the high waters due to excessive rains; hence it took no little stretch of the imagination to realize the great influence these falls had had upon the development of the Middle West. But George Rogers Clarke appreciated the importance of this interruption of the navigation of the Ohio as early as 1778, and made the beginning of the present important city of Louisville.

The next falls of note are the Kanawha Falls, about a mile below the point where the clear waters of the Gauley River join the boiling chocolate of the New to form the Kanawha. These picturesque falls at the entrance of the beautiful gorge of the New River have as yet exerted little power as an urban stimulus, the result being the miserable little village of Stockton. Notwithstanding the insigficance of this hamlet, chromium from Turkey, Caledonia, Brazil, and Canada has found its way here to meet the coal, iron, and sand of the region, and armor plate for war vessels is the result.

The last falls seen going down the James River are of great importance, for they have given to Virginia her famous capital, and have stimulated many industries.

Of the numerous factories which line the banks of the James River at Richmond, we visited but one-a blotting-paper manufactory. We were surprised to learn here that American rags are not sufficiently worn to be used in making the finest blottingpapers, and that "best rags" are imported from Egypt, Turkey, Greece, and Germany. Whether our deficiency in this line is 'Geologic Atlas, Charleston Folio, 1901.

due to our wealth or extravagance may be a debatable question, yet either seems comforting when one gazes upon the great piles of unspeakable, evil-odored rags, and he wonders if the tenhours' boiling in caustic soda will be sufficient to sterilize the impurities of Europe and Africa. Apprehensive of the danger in such importations, one almost wishes, even in this free-tradeloving region, that there were a prohibitive tariff upon such imports.

While the rapids and falls stimulate manufactories and the growth of cities, the flood-plains of the rivers denominate the rich agricultural lands of many districts. The contrast between the fertile plains along the James River and the exhausted uplands of Virginia is forced upon the attention of the most listless observer. The value of rivers as giant excavators, laying bare the secret riches of the earth in the form of building-stone, minerals, metals, oil, and gas, is strikingly illustrated in the Kanawha and New River valleys from Charleston to Quinnimont, W. Va., a distance of about seventy-five miles. Here the cliffs, almost perpendicular in places, rising seven or eight hundred feet above the water, are perforated from top to bottom with coal shafts. The buildings at the mouths of the shafts cling to the tree-covered rocks as woodpeckers to the trunk of a tree, while the coke-ovens make a necklace of fire along the seething waters of the New River.

Tides. The recent sinking of the Coastal Plain has so depressed the river valleys as to allow the influence of the tides to be felt many miles back from the sea. The ebb and flow in the James River reach as far as Richmond, eighty-five miles from Old Point Comfort. Even the creeks in the lower Coastal Plain are wide, navigable, tidal rivers.

Waves and currents.-The coast between Virginia Beach and Willoughby Spit affords an excellent opportunity for the study of the work of waves and currents as well as of tides. Willoughby Spit, which is about eight miles north of Norfolk, is a typical fish hook of sand, built by the waves and currents for almost three miles out into Hampton Roads. The end of the spit is about equidistant from Old Point Comfort.

Work of wind.-The coast also furnishes the best place for the study of the work of wind. A great amount of sand is brought up by waves and currents along the Atlantic in this district, providing material which can be easily transported by the wind. The best example of aeolian deposit is found at Cape Henry. The sand stretches for miles along the coast and reaches back from the famous Cape for about a mile and a half in beautiful cream-colored billows, whose crests rise eighty feet above the sea, burying the struggling forest under their smothering weight.

Diastrophism-rising and sinking of the land.-Changes of the surface of the land are not due to the agents of water, ice, and wind alone; for evidences of the internal movements of the earth are seen, not only in the displaced, folded, and contorted rocks of the Appalachian Mountains and the Piedmont, but also in intrusions of igneous rocks in the Piedmont. The records of recent changes in the relation of the land and the ocean are found in the "drowned" valleys of the Coastal Plain-the Chesapeake Bay and the tidal stretches of the James, York, and Potomac Rivers. Old pine-tree stumps, which now stand in the Chesapeake Bay at Buckroe Beach near Old Point Comfort, bear evidence of very recent encroachment of the sea in this region.

Historical geology.-The birthdays of landscapes are not marked by the dial of a clock, but by great changes in the surface of the land. When the land has risen after the encroachment of the sea, as seen in the Coastal Plain, a marine deposit is left over the valleys, plains, and hills.

From the evidences of such events, and the changes in life left as fossils in the rocks, geologists have been able to interpret a part of the history of the earth.

By examining a geological map of the eastern portion of the United States, it will be seen that in a trip from Chicago to the Atlantic Ocean one passes over rocks representing all the geologic eras and periods which man has devised for the classification of the great events of terrestrial history. The oldest rocks are called Archeozoic, and are found between the "Fall Line"

• The Proterozoic are here included under Archeozoic.

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