“ Many mineral springs are found along lines of faulting, since fault fissures afford a means of escape. The dissolved mineral substances no doubt are obtained from the rocks through which the water has flowed. In some cases the waters in seeping through one type of rock may take up certain acids which later react on basic elements contained in other rocks, thus producing salts. Most waters contain some carbonic acid, which greatly increases their solvent powers in the presence of lime, magnesia, and iron ”

“ The general character of the springs of Virginia and West Virginia is saline; sulphureted waters are the most numerous, but alkaline and chalybeate and acid springs also occur. The saline springs are found in excess of all others in the South Central States, and thermal springs are few. In this region the States of Kentucky, Tennessee, and Arkansas are the chief producers of mineral waters. The Hot Springs of Arkansas are among the most important thermal springs found in the entire country, and of value for diseases of the blood. ”

“ The attacking power of the water may be still further increased if it is hot. There seems to be some relation between hot springs and the geological structure of a region, as thermal springs are more abundant in areas where the rocks have been highly faulted or where there has been volcanic activity in comparatively recent geological times. Mineral springs commonly contain more dissolved material in regions of sedimentary rock formation than in igneous or metamorphic areas. ”