VIEWS OF VARIOUS GEOLOGISTS 475 



Nuovo to illustrate the formation of tuff cones, emphasizing the brevity 

 of the process, the stratification of the material (double quaquaversal), 

 and the lack of any disturbances in the adjacent territory. The temple 

 of Pluto was partly covered by the debris, but its level has not been 

 affected, as it would have been if the cone had been formed in the manner 

 suggested by L. von Buch and Elie de Beaumont. They believed that 

 the conical shape proceeded from an upheaval or swelling of the ground 

 around the vent from which the materials issued. 



Dr J. C. Branker's Statement 



Doctor Branner comments on the tuff and talus of Diamond head.* He 

 finds present an extensive mass of talus over tying calcareous sand, both 

 lying at an angle of 30 degrees; and the talus contains land shells. He 

 thinks Doctor Dall must refer to that talus when he says the tuffs overlie 

 the calcareous beds. He believes the tuffs were land deposits and did not 

 come from beneath water level. Doctor Dall in his reply f calls attention 

 to the fact that Doctor Branner did not see the region farther around the 

 cone upon which he had based his conclusions, and that the limestones 

 carrying the fossils (marine) could not have been a subaerial formation 

 (blown sand). Doctor Dall evidently would not disagree with the 

 statements about the relative positions of the blown sand and the talus 

 carrying the land shells, as both authors examined the same quarry. 



Dr Whitman Cross's Statement 



Doctor Cross remarks as follows:.! 



"The view of Doctor Dall that the whole mass of Diamond head had been 

 slowly deposited in comparatively shallow water and gradually elevated with- 

 out being subjected to notable flexure seems to the writer incorrect for various 

 reasons, some of which have been pointed out by Dr J. C. Branner and Dr 

 S. E. Bishop." 



The subject was referred to incidentally in speaking of Doctor DalPs 

 determination of the Pliocene age of the rocks in a part of Oahu. 



The latest Views of Doctor Dall 



Several letters have passed between Doctor Dall and myself concern- 

 ing the special features of Diamond head. Explanations more explicit 

 than those here printed have been given, and in 1905 I endeavored to visit 



* Amer. Jour. Sci., vol. xvi, 1903, p. 306. 

 t Amer. Jour. Sci., vol. xvii, p. 177. 

 t Journal of Geology, vol. xii, p. 519. 



