76 THE BERMUDA ISLANDS. 



tion of a seawardly-extending talus of coral is, it appears to 

 me, purely gratuitous. Indeed, with the very gentle slope that 

 these islands have beneath the sea it is extremely doubtful if 

 any extensive talus could accumulate as a result of either 

 downflow or downwash. Prof. Dana has well supplied the 

 argument on this point, and its seems to me that it is unan- 

 swerable. With a gradient of perhaps eight degrees, and 

 not impossibly much less, it is almost inconceivable that there 

 should be much lateral spread of detached coral boulders. 

 Neither wave-action nor the action of the oceanic currents, 

 except possibly under conditions of earthquake disturbance, 

 would be likely to effect the required displacement. 



Again, it might be asked, what kind of direct evidence must 

 we look for to establish the point that there has been no great 

 progressive subsidence in tlie Hawaiian Islands? The needed 

 evidcHce is just of that kind which it pleases the Earth to keep 

 to herself, and after which the geologist has in most instances 

 sought in vain. The fact that cinder-cones are found " with 

 their base close to the present sea-level " proves, it appears to 

 me, nothing in this connection, and I fail to see the argument 

 which draws from their existence a proof of non-subsidence. 

 But Agassiz himself admits tliat there is " some evidence of 

 subsidence [about 50 feet] on the southern shore of Hawaii" 

 (p.' 154). 



On the whole, it seems to me, that the facts as they are pre- 

 sented are, if tliey indicate anything at all, directlj' in favor 

 of subsidence, and of subsidence on an extensive scale. They 

 are in my mind far more conclusive than the somewhat simi- 

 lar facts which have been generally accepted by geologists to 

 j)rove depression or subsidence in delta-deposits, such as those 

 of the Mississippi or Ganges. Dr. \V. 0. Crosby, in his paper 

 on "The Elevated Coral Reefs of Cuba,"* shows that the coral 

 limestone of Cuba is in places at least a thousand feet in 

 tliickness, and he naturally infers that there must have been 



*Proc. Boston Soc. Nat. History, XXII, 1882-83, p. 124. 



