390 Notices respecting New Books. 



points of general interest, such as every intelligent reader, not 

 being a geologist, may comprehend. For the most part the Chapters 

 may be read as complete Essays on the many subjects necessary 

 for a geological student to know, written in a fairly popular style, 

 though enriched with all the necessary details and references to 

 authorities. 



In the First Volume the natural causes and methods of the 

 wearing-away and decomposition of rock-masses, and the variable 

 rearrangement of the resultant material are first of all explained, 

 being highly important in the consideration of Denudation and its 

 results — as to local decrease of land and accumulation of various 

 deposits in water all over the globe. The water-question is specially 

 treated by one who has traced the rain-water in its underground 

 ways to natural springs and rivers, and to the supply of artificial 

 wells and borings. The part played by water in volcanic eruptions, 

 nearly a new subject, is fully described. Ice and snow have their 

 special chapter also. Alterations in level of the earth's surface, 

 whether effected by earthquakes, by the lateral pressure of great 

 contractions, or by coral-growths, have their interesting and 

 instructive chapters ; and the important subjects of faults in dis- 

 turbed strata, joints, cleavage, mineral veins, old volcanic rocks, 

 metamorphism, and all the conditions of mountain-ranges, whether 

 continental or local, are treated of in essays full of facts and bold 

 generalizations. Chapters xviii. and xix., on metalliferous deposits, 

 treat of their endless varieties of veins and lodes, their geological 

 and geographical distribution, and the various results of their 

 decompositions. All this is in close association with the foregoing 

 subjects, and together with the preceding essays, while supplying 

 the general reader with useful resumes of what is known, elucidated 

 by many new ideas, meets the requirements of the advanced student. 

 It enables him to understand more fully the various physical and 

 chemical problems offered by geology, in studying the unceasing 

 series of changes dependent on the circumstances of the time, as 

 new conditions and new combinations successively arose in the 

 course of the earth's long geological history, with constant variation 

 in degree and intensity of action. 



The Second Volume treats of the history of Strata, their appear- 

 ance, conditions, and constitution having been described in 

 Volume I. The succession of recognizable groups of Strata in 

 different parts of the "World, as at present known, is shown by 

 several Tables in chapter i. The great geological systems or series, 

 as defined by their relative unconformity, or differences of position, 

 and by the organic remains peculiar to each, are then taken in hand, 

 one after the other, from the oldest to the latest. Their fossils, 

 whether of animal or vegetable origin, are carefully noted and often 

 tabulated at some length. They are illustrated with many wood- 

 cuts and lithographic plates, all good artistic work, and all new 

 except some borrowed from modern works on special groups and 

 of great merit. The fossils figured have been selected with real 

 scientific care, and some microzoa, not usually thought of so much 

 as they should be as rock-makers, are introduced with good effect. 



