are then taken up and described as applied to land forms in regions of horizontal, or gently inclined, and of highly folded and disturbed strata, and in regions affected by normal faults or vertical displacements. Land forms due directly or indirectly to igneous action and the influence of rock character on the determination of land forms are subjects of special chapters. Glacial action is one of the most important factors in modifying the forms of northern lands, and is treated with considerable fullness. Æolian action--of the air and wind--has peculiar and important effects in arid regions, and underground water in limestone districts, and these receive attention. Then come basins--those due to crustal deformation, crater lakes, river lakes, glacial basins, and others, and coast lines. Finally, a classification is given of these land forms as plains or plateaus of accumulation and of erosion, original or tectonic and subsequent or relict hills and mountains, original or tectonic and subsequent or erosion valleys, basins, and coast lines, and the conclusions are reached that we do not know, except as a matter of probability, whether we have still visible any original wrinkles of the earth's crust; and that some of the estimates of the time it has taken to produce the changes of which we witness the results have been very much exaggerated. The curious conclusions obtained by Dr. _Le Bon_ in his psychological investigations,[15] delivered to us in startling language, are said to be the fruit of extensive travel and of the personal measurement of thousands of skulls. His memoir on cervical researches, published in 1879, upholds the theory that the volume of the skull varies with the intelligence. This theory has perhaps suffered a permanent adumbration. Facts seem to prove that the bony structure of the skull, or even its cranial capacity, gives no positive indication of intellect.