PHTSICiJ. GEOLOGY. 163 



Urges that while barrier-reefs are proofs of subsidence, "small or 

 fringing reefs are in themselves no certain evidence of a stationary 

 level, and are often evidence of subsidence." Keasons are given for 

 difiering from Mr. Darwin as to the limits of the areas of subsidence 

 and elevation in the Pacific. G. A. L. 



Daxa, Prof. J. D. Coral Reefs of Hawaii. Amer. Journ, ser, 3, 

 vol. viii. p. 466. 



Ellis states that round several parts of Hawaii there are raised 

 coral-reefs, twenty feet above the sea-level ; this is an extract from a 

 letter, denying the statement. A. H. G, 



DiEFFENBACH, F. Die Erdbeben und Yulkanausbriiche des Jahres 



1872. N. Jahrb. Heft ii. pp. 155-163. 

 A record of earthquake and volcanic activity during the year 1872. 



Everett, Prof. J. D.^ Sixth Report of the Committee on Under- 

 ground Temperatures. Rep. Brit. Assoc, for 1873, pp. 252-256. 



In the boring of the well of La ChapeUe, Paris, the increase of 

 temperature down to a depth of 600 metres was pretty regular, at an 

 average rate of 1° F. for every 94 feet : 60 metres lower an increase 

 about four times as rapid was found, which was conjectured to be due 

 to the heat produced during the boring-operations. This conjecture 

 was found to be correct. After the water had stood undisturbed for 

 sixteen months, a fresh set of observations was taken : the tempera- 

 tures down to 600 metres were sensibly unchanged ; the temperature, 

 at a depth of 660 metres had fallen from 83°-25 to 76°. The average 

 rate of increase was 1° F. for 94-3 feet, if the temperature at a depth of 

 100 metres be taken for the invariable temperature; 1° F. for 84 feet, 

 if the temperature of the caves under the Paris Observatory be so taken. 

 At the Kentish-Town well the thermometer, placed at a depth of 

 1000 feet, has been raised and read three times ; it shows each time a 

 decrease in temperature ; Mr. Symons is discussing this result. 

 Mr. Lebour reports that the abnormal increase of temperature observed 

 in the South-Hctton bore-hole arose from insufS.cient time having been 

 allowed to the thermometer. A. H. G. 



. On Underground Temperatures. Proc. Belfast Nat.-Hist. 



and Phil. Soc. 1873-74, pp. 41-50. 

 A resume of the observations and reasonings of the author and 

 others. Full references. 



Fisher, Rev. 0. On the Formation of Mountains, viewed in con- 

 nexion with the Secular Cooling of the Earth. Geol. Mag. dec. 2, 

 vol. i. p. 60. 



Outline of a paper read to the Cambridge Philosophical Society. 



. On the Formation of Mountains; being a reply to Capt. 



Button's article, p. 22 of same volume. Geol. Mag. dec. 2, 

 vol. i. p. 64. 



M 2 



