122 



Galapagos Archipelago. 



PART I. 



layers. Tliese interior converging beds, as well as the 

 proper, diverging, crateriform strata, are represented 



Xo. 13. 



A sectional sketch of the headlands forming Banks' Cove, slxraing the diverging 

 crateriform strata, and the converging stratified talus. The highest point of 

 these hills is 817 feet above the sea. 



in the accompanying rude, sectional sketch of the head- 

 lands, forming this Cove. The internal and external 

 strata differ little in composition, and the former have 

 evidently resulted from the wear and tear, and re- 

 deposition of the matter forming the external crateriform 

 strata. From the great development of these inner 

 beds, a person walking round the rim of this crater 

 might fancy himself on a circular anti-clinal ridge 

 of stratified sandstone and conglomerate. . The sea is 

 wearing away the inner and outer strata, and especially 

 the latter : so that the inwardly converging strata will, 

 perhaps, in some future age, be left standing alone — a 

 case which might at first perplex a geologist. 1 



James Islaxd. — Two craters of tuff on this island 

 are the only remaining ones which require any notice. 



1 I believe that this case actually- occurs in the Azores, where 

 Dr. Webster (< Description,' p. 185) has described a basin-formed, 

 little island, composed of strata of tufF, dipping inwards and 

 bounded externally by steep sea-worn cliffs. Dr. Daubeny supposes 

 (on Yolcanos, p. 266), that this cavity must have been formed by a 

 circular subsidence. It appears to me far more probable, that we 

 here have strata which were originally deposited within the hollow 

 of a crater, of which the exterior walls have since been removed by 

 the sea. 



