Notices respecting New Books. 213 



adaptable as the quadrilateral to various circumstances. I 

 need say nothing as to its theory, that having been, I under- 

 stand, treated by Prof. Chrystal. Using a pair of equal coils, 

 it is very similar to that of the equal-ratio quadrilateral. 

 December 29th, 1886. 



XXII. Notices respecting New Books. 



The Origin of Mountain-Ranges, considered Experimentally, Struc- 

 turally, Dynamically, and in Relation to their Geological History. 

 By T. Mellaed Reade, O.E., F.G.S., F.R.I.B.A. London: 

 Taylor and Francis, 1886. 

 TT is now twenty years since Mr. G-eorge L. Vose published his 

 -*- ' Orographic Geology/ containing an admirable review of all 

 that had, up to that time, been done in the way of explaining the 

 structure and origin of mountain-chains. Strange to say, the 

 author of the work now before us does not appear to be acquainted 

 with the labours of his predecessor in the same field ; but the large 

 amount of original research bearing upon the subject ia question, 

 which has been carried on in the interval, fully justifies the pre- 

 paration of this new book by one so competent to undertake it as 

 Mr. Mellard Eeade has shown himself to be. 



The author aims at nothing less than framing a complete and 

 consistent theory of the origin of mountain-ranges ; and whatever 

 divergences of opinion may arise as to the soundness of particular 

 portions of that theory, or of the force or value of certain of the 

 arguments by which they are supported, there can be no hesitation 

 among candid readers in admitting the great value of the mass of 

 facts relating to the question which have been obtained by the author 

 by ingenious experiment and patient observation, or the interest 

 attaching to the conclusions which he has founded upon those 

 facts. 



If the theory, as a whole, can lay no claim to absolute novelty, 

 there are certain new and striking features introduced into it by 

 the author, and the principles on which it is based are certainly 

 exemplified and enforced by him with much freshness, ingenuity, 

 and vigour. 



Mr. Mellard Reade insists on the principle so well recognized by 

 Hall, Rogers, Dana, Le Conte, and most recent authors who have 

 treated on the subject, that the first stage in the origination of a 

 mountain-chain consists in excessive sedimentation. After giving 

 an outline of the main facts made known by recent researches 

 concerning the Appalachians, the Rocky Mountains, the Andes, the 

 Himalayas, the Alps, and the mountains of our own islands, he sum- 

 marizes his conclusions as follows : — " No great range of mountains 

 was ever ridged up excepting in areas of great previous sedimenta- 

 tion. Out of these sediments the mountains are mostly built and 

 carved, but along with the newer and originally horizontal sedimen- 

 tary beds, the older gneissic and Archa3an rocks are usually thrust 



