National Geographic : 1896 May
GEOGRAPHIC LITERATURE uplift, deformation, or other genetic processes, the succeeding work of the agencies of erosion, the control of dissection by the effective baselevel, the gradual and systematic progress in dissection as determined by the advance in time through the geographical cycle, and the termination of the normal uninterrupted cycle of erosion in a plain or peneplain of sub aerial denudation, all these and many other essential features of the American treatment are succinctly presented. Numerous illustrative ex amples, largely taken from European sources, are presented; these being of particular value to our students of the subject, who are naturally more familiar with American occurrences. Following the statement of general and special principles, there comes an account of Europe in particular and of the world in less detail, which is, I believe, the first serious attempt to treat areal geography in this fashion. Local geomorphological studies have been' attempted elsewhere, but no one has hitherto undertaken to discuss the physical geography of the world on these new lines. It goes without saying that the treatment must be very unequal, for the physiog raphy of many parts of the world is now as little known as the fauna and flora of the remoter regions were known a century ago. It is manifest from an examination of this book, as well as from the study of various other sources, that the morphology of mountains is in a much less advanced state than that of simpler -structures; Students of the subject will therefore do well to give particular attention to remedy ing this deficiency. At present we read frequently about the height and length of ranges, about the rocks of which they are composed, and about the influence of mountains on climate, both local and adjacent, as well as about their control of the character and distribution of plants and animals, but it is very seldom that any critical or detailed morphological account is given of the mountains themselves. Their forms are so various, so ungeometrical, that they have not yet been reduced to system and embodied in a satisfactory terminology, indicative of structure on the one hand and of stage of destructional development on the other. Thus de Lapparent's account of the concentric escarpments of the Paris basin is more systematically complete than his description of the Pyrenees; a clearer idea is given of the topography characterizing the simplified forms of the old mountains of the middle Rhine than of the complicated forms of the still vigorous Alps. This is not to be avoided in the present stage of the science, but nothing will aid more in carrying us past this stage than the preparation of sound general treatises like the one before us. Its perusal must turn many students toward further investigation, and new investigators are greatly needed. In the matter of citations, the author has been sparing, but this is to be the less regretted on account of the exhaustive bibliographic treatment of geomorphology in Penck's recent Morphologie der Erdoberfldche (2 vols., Stuttgart, 1894). The latter book presents an exceptionally full account of the historical development of physical geography, while the former presents a concise account of its present advanced condition, and thus the two works complement each other very satisfactorily. Whether in preparation for a trip abroad or for use in study and teach ing at home, de Lapparent's Lemons must prove very acceptable to Ameri can geographers. W. M . DAVIs.