474 C. H. HITCHCOCK GEOLOGY OF DIAMOND HEAD, OAHU 



crease the velocity and reduce the time, with a sectional area of 5,000 

 feet. 



These statements of the symmetry of the cone and of the time re- 

 quired for the deposition of the mass are thought to forbid any other 

 conception of formation. A very good map of the Head and immediate 

 surroundings accompanies this paper. 



Writer's Statement at the Albany Meeting 



At the Albany meeting of the Geological Society of America I pre- 

 sented briefly the antagonistic views of Doctors Dall and Bishop and 

 requested the opinions of the fellows present as to the proper position to 

 be taken in the controversy. No one offered any suggestion.* 



Doctor Dall's reply to Doctor Bishop 



Doctor Dall comments on this paper in the American Geologist for 

 June, 1901,f practically as follows: 1. Diamond head as described by 

 Doctor Bishop does not exist. 2. The observations previously stated are 

 reaffirmed. 3. The inferences are submitted to the criticism of experts. 

 4. The tuff is underlaid by limestone carrying Chama and Ostrsea, and 

 in the middle part of the cone there are horizontal layers of compacted 

 coral sand out of which the calcareous snowy crusts have been bleached. 



Archibald Geikie's Comment 



In his text book of Geology, J Sir Archibald Geikie refers to Doctor 

 Bishop's paper thus : "On the transient character of the volcanic action 

 in the case of tuff cones, see Bishop, American Geologist, vol. xxvii 

 (1901), page V 



He also compares the action of Diamond head to the eruption of Monte 

 Nuovo, near Naples, in 1538, when a tuff cone was formed in twenty- 

 four hours. I have myself ascended the sides of this cone, which has 

 the altitude of 489 feet, and is about one and a half miles in circum- 

 ference. The larger part of the famous Lucerne lake was filled with 

 the stones, scoria, and ashes ejected in 1538. Among the fragments 

 ejected were pieces of Eoman pottery and marine shells, which happened 

 to be situated in the path of the ascending outburst. I have been in the 

 habit for the past forty years of using in my lectures the history of Monte 



* Bull. Geol. Soc. Am., vol. 12, p. 462, 

 fVol. xxvii, p. 386. 

 J Vol. 1, p. 326. 



