178 Recent Literature. [Febr aiy, 
So extremely hypothetical, from paleontological considerations, | 
is the evidence of so-called “interglacial periods,” referred to on 
p. 29, that we wonder that our author should endorse Dr. Croll’. 
speculations without stating some of the facts supposed to sustain 
such a view. 4 
The age of the earth is, from facts relating to erosion, set down 
as “not much less than 100,000,000 years since the earliest form 
of life appeared upon the earth, andthe oldest stratified roc 
began to be laid down;” this length of time, from the standi 
point of physics, as advocated by Sir William Thompson, is tie 
same, while Tait’s estimate of fifteen or twenty millions is give 
although based on “results confessedly less emphatic than 
derived from the facts of erosion, of physics and of tidal re 
tion.” 
- The author treats of the upheaval of land under dynam 
geology, but reserves his brief discussion of the mode of 
tion of mountain chains and of continents for the sect 
physiography; we should think all these subjects would 
under the head of dynamical geology. Neither has he 
ently availed himself of Darwin’s and Mr. A. Agassiz’s fac 
cerning the secular rise of the South American continen 
devotes less than a page to the grand theme of the evolu 
e American continent; and in this part of the book we ! 
Professor Geikie has not risen to the grandeur of the subject. 
_- The care and elegance of the author’s style; the genera 
cellent and apt illustrations; the typographical appearance 
book, allow little or no room for criticism. One geogra 
Wyoming.” = 
_ While this Text 
t Knocking round Aree a: Di i H 
; : Ries. By ERNEST INGERSOLL. Illustrated. 
Harper & Brothers, 1883. Large 8vo, pp. 220. $2. | 
