238 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



Another fact which agrees with the theory that there has 

 been a former land connection between at least many of the 

 islands, is the shallowness of the water between most of them. 

 An elevation of one hundred fathoms would connect all the 

 southern islands, and a rise of seventy-one fathoms would 

 bridge all of these except Chatham, Hood, and James, so far as 

 the soundings that have been taken show. The only deep 

 soundings known are between Abingdon and Wenman, 1189 

 fathoms, between Bindloe and James, 684 fathoms, and between 

 James and Tower Islands, 885 fathoms, depths of water which 

 are not difficult to account for if one does not maintain too 

 strongly that all of the islands were formerly connected into a 

 single large one. 



Considering the volcanic nature of the islands, the general 

 shallowness of the intervening water lends support to the sub- 

 sidence theory, for it is hardly likely, if all of the bed of the 

 ocean between the islands had been formed by marine volcanic 

 activity, that the lava would have been so evenly distributed 

 over this bed without leaving at least a few abysses. The grad- 

 ual deepening of the water away from the shores of many of the 

 islands also supports the subsidence theory, especially when we 

 consider the fact that the slope of the submerged portions of 

 some of the islands approximates the slope of the lower parts 

 above water. 



While all of the above facts seem to point to a general sub- 

 sidence of the islands, there are a few evidences of elevation. 

 On both Indefatigable and Seymour Islands there are deposits 

 containing a considerable number of marine fossils which have 

 been elevated a few feet above the level of the sea. The great- 

 est amount of elevation seems to have taken place on Albemarle 

 Island. Snodgrass and Heller, of the Hopkins-Stanford Expe- 

 dition to the Galapagos Islands, thought that they detected 

 signs of elevation at Tagus Cove on the west side of this 

 island. There is evidence of some elevation at the south end of 

 Albemarle, concerning which Mr. W. H. Ochsner, the geolo- 

 gist of the Academy's expedition, has been kind enough to 

 furnish the following information : 



"About one and one half miles inland from the settlement near 

 Turtle Cove on the south shore of Albemarle Island, there is exposed 

 a rather large remnant of an old sea beach. The deposit exists as 

 white sands several feet thick and composed entirely of the fragments 

 of coral, molluscan and echinoid, and other calcareous marine forms. 



