IRON ORES OF THE PALEOZOIC FORMATIONS.
ferriferous region which we propose.to describe under this head lies principally in the limestones and slates of the Great Va!lley range, between the Blue Ridge and the Alleghany Mountains, or the brown hematite region, between the Potsdam and Medina sandstones and the stratified ores of the Carboniferous formations, but inclusive of the beds lying intermediate or in the Devonian rock, The Valley range is the great region of brown hematites, and embraces generally the Primal slates, the Auroral and Matinal limestones of Rogers, or the Hudson, Trenton, Chary, and Calciferous limestones of the New York geologists, and the Galena and Calciferous limestones of the West.
These rocks hdve a wide distribution, and are only separated from the Azoic by the Potsdam sandstones in the East, and probably a lower formation of fossiliferous strata in the West, resulting from the comparative quiet and low temperature that existed there, in comparison with the violence and heat of this period in the East as before stated. These formations, therefore, follow closely the Azoic belt, but on interior lines, and they are, consequently, of more limited extent, but form the base of the vast Palm ozoic formation filling the great basin; and, since they are from one thousand to five thousand feet in thickness, the area occupied by these limestones is not only extensive, but widely distributed.
Starting from the alluvial deposits of the Gulf, they traverse the northeastern part of Alabama, the northern part of Georgia, and form the beautiful and productive val leys of East Tennessee; the great Valley of Virginia through that State, from Bristol in the southwest to Harper's Ferry on the Potomac; the rich Cumberland Valley in Maryland and Pennsylvania, and the magnificent regions around Harrisburg, Lebanon, Reading, Allentown, and Easton; through the northwest corner of New Jersey, and by the valleys of the Hudson River and Lake Champlain through New York into Canada; and thence, ascending the St. Lawrence, skirts the north shores of Ontario,
and, passing through the Georgian Bay of Lake Huron, sweeps round the north and west sides of Lake Michigan, and pursues a nearly west course through Wisconsin to the Mississippi. The granitic and gneissic mountain-regions of Northern New York are thus placed inside of this limestone belt; but this may be explained by the fact that the Palveozoic limestones and slates divide to the south of this gneissic elevation and pass around it to the eastern shores of Ontario, thus encircling this isolated Azoic for mation by the later Paltww.oic strata.
Those eastern and northern outcrops of these rocks are well defined and of great thickness and extent. The western margins are not so clearly shown; their outcrops are thin, indefinite, and but seldom seen. Several anticlinal axes of the lower Palm ozoic strata arise within the Great Basin. One traverses Middle Ohio, Kentucky, and Tennessee, between the Alleghany and Central coal-fields, and spreads west around the southern end of the coal formations in Missouri, encircling the Azoic rocks of the Ozark Mountains, and bounding the Washita Hills in Arkansas and the granite peaks of Central Texas; while within the Eastern Appalachian chain several anticlinals of this limestone appear in Pennsylvania and Virginia.