Revieivs — Observations on a Florida Sea-beach 517 



determined, and the amount reported as water should not include any- 

 other substance given off at the same time. 



In the absence of facilities for obtaining rock analyses, petrological 

 work in this country is at present seriously handicapped. A striking 

 illustration of the inadequate provision for analyses is revealed in the 

 fact that for the whole of the early Permian granitic intrusions in the 

 South-west of England, covering nearly 2,000 square miles, and 

 including numerous different types and varieties, there are only four 

 analyses in existence, and of these two are out of date and imperfect. 

 This is all the more remarkable in view of the fact that these rocks are 

 closely connected with the pneumatolytic action that has given us 

 almost all the economic minerals of the South-west of England, 

 comprising ores of tin, tungsten, copper, lead, and uranium, as well 

 as kaolin. If the Survey, by increasing its staff of analysts, were in 

 a position, not merely to multiply the number of analyses illustrating 

 its own work, but to help others engaged in research, they would 

 only be proceeding on lines which have long since been followed in 

 some of our Dominions. 



(To be continued.) 



I?.E"VIE-V\rS. 



I. — Mountains. By C. A. Cotton, D.Sc, F.G.S. New Zealand 

 Journal of Science and Technology, vol. i, No. 5, pp. 280-5, 1918. 



IN this paper Dr. Cotton points out that the distinction commonly 

 drawn between fold-mountains and mountains of circumdenuda- 

 tion needs qualification in those cases where the denudation is now 

 in a second or later cycle, owing to superposition of block-structure 

 with uplift on original folding. He considers that in many cashes 

 the erosion directly due to uplift was a comparatively short-lived 

 process, and that the present mountains owe their elevation and 

 relief to causes operating long after the folding had ceased. It is 

 shown that certain of the mountains of New Zealand owe thfir 

 present condition mainly to the Kaikoura orogenic movements, 

 which were differential uplifts and not folding. New Zealand may, 

 in fact, be described as a concourse of earth-blocks, the highest on 

 the north-eastern and south-western axis of the land mass, and in 

 places portions of the old marine plain of deposition can be recoanized 

 on the denuded surfaces of the uplifted and tilted blocks. This is 

 an idea which has perhaps been insufficiently considered by physio- 

 graphers, and the points raised are worthy of careful study, as they 

 may be equally applicable to other regions. 



II. — Observations on a Florida Sea-beach, with special reference 

 to Oil Geology. By G. F. Kemp. Economic Geology, vol. xiv, 

 pp. 302-23, 1919. 



DURING a residence of two winters on the coast of Florida 

 Mr. Kemp devoted a considerable time to the detailed study 

 of the character and formation of the beach and the changes 



