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inclusive, are devoted to the detailed description of the local geology of each of the counties embraced in this region.

Part II (chapters XXI-XL inclusive) deals with the Economic Resources of the Paleozoic group, which are limonite, hematite, manganese ores, beauxite, coal, limestones, sandstones, and clays. The mode of occurrence of these materials, their distribution both geographical and geological, their analyses, etc., are shown forth in sufficient detail, and a commendable feature of Dr. Spencer's treatment is found in the explanations and suggestions as to the origin of these various ores, expressed in terms which are easy of comprehension even by those who have not had any special geological or chemical training. In this way the book has a direct educational value apart from the great amount of information as to local occurrences which it contains. The chapter of beauxite is of special interest, because of recent developments in the mining and shipping of this valuable substance from the Georgia and Alabama mines. The occurrence and general character of the ore in the two states are identical, in fact the ores belong practically to a continuous deposit, in close connection with the strata of the Knox Dolomite. On account of competition with the foreign beauxites, only the higher grades of the ore, containing from 55 per cent. and upwards of alumina, are shipped, and by far the greater part of this goes to the making of alum. This seems a wanton waste, since the inferior grades would answer for alum, and the higher grades should be reserved for the manufacture of the metal.

The coal of Georgia is confined to an area of about 200 square miles on the plateaus of Sand and Lookout Mountains. It is furnished almost entirely by two or three seams lying between the Upper and Lower Conglomerates near the base of the Coal Measures, as is the case also in Tennessee and the Plateau region of Alabama. In all this territory, these seams and the strata by which they are separated, are exceedingly variable in thickness. The most widely distributed of these is the Castle Rock seam just below the Upper Conglomerate (Main Etna and Cliff seams of Alabama and Tennessee). In Georgia the Dade seam, some 30 feet or more below the preceding, appears to be more extensively worked, and, in the sections given, of greater average thickness. This seam also has been worked in Alabama, where it is known as the Eureka seam. Still below this in all the states mentioned is another seam of great importance locally, the Red Ash seam.

In one locality, Round Mountain, which rises above the Lookout