Congressional Edition Volume 5979 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 Excerpt: ... be developed. It follows that slates do not occur in regions of horizontal rocks; nor can they by any means be expected in all regions of folded rocks. THE SLATE AREA OF ARKANSAS. The area of Arkansas in which the surface rocks are folded, and in which consequently slate might be looked for, is in the central-western part of the State (fig. 24). It lies between Arkansas River and the northern parts of Sevier, Howard, Pike, and Clark counties, west of the St. Louis, Iron Mountain and Southern Railroad. It must not be understood that all parts of this area contain slate; for in the formation of slate not only must dynamic agencies so act upon the rocks as to compress and throw them into folds, but the originally deposited material from which the rocks were formed must have been mechanically and chemically suited to undergo metamorphism into slate. Most slate is metamorphosed shale. Shale is common over all parts of the area mentioned above, and folding in many parts has been so intense as to cause the strata to stand on edge or even to be overturned; yet slate is confined to a comparatively small area, because within that area only were the shales of such a nature as to permit their alteration into slate. The area in which the slates of Arkansas are situated includes a part of the Ouachita Mountains and extends from the vicinity of Little Rock westward to that of Mena. Its length is about 100 miles and its average width 15 miles. It lies mainly in Saline, Garland, Montgomery, and Polk counties. The St. Louis, Iron Mountain and Southern Railway runs near the eastern border, and the Kansas City Southern Railway near the western border. The Little Rock and Hot Springs branch of the Chicago, Rock Island and Pacific Railway enters the area. The St. Louis, Iron Mo...