358 MOLLUSKS iW THK GALAPAGOS STEARNS. 



Nepeau, oii .lames Islaiul, and Alheiiiarlc in (lie diit'ction of Cowley 

 Island, Narboroii.uh itself beiiij? only separated iVoni Albcniaile by a 

 elianiiel less than 7r> fathoms in (lepth. The sonndinji's between Cliat- 

 bani, lianin<;ton, and Ilood are so few in nnnd)er that we are not yet 

 able to decide whether tliese sontlieastern islaiuls, Chathain and Tlood, 

 are not perliai»s eo'^uieeted by a rid<;e eoniieetin^" Hood and .Maes^'owen 

 Eeef, and also nnitin-;- tlieni Avith the jjreat ])lateau wiiicli the islands 

 of i^>arrinyton, diaries, Indefatigable, Dnncan, Albemarle, Narborough, 

 ami perhaps James iiave tiradnally bnilt up. 



"But it may be that the tontiiie of deeju'r water extendinji' between 

 Hood aud Chathain runs toward liarrin.nton, and also separates that 

 island from Chatham." 



Agassi/ farther on says: "On account of the small number of sound- 

 ings, no attempt has been made to draw curves of depth on the chart 

 of the dalapagos." 



OKKJIN TIIKOUGII Sl^BSIDENCE. 



The position of Baur is that "///<; (i((l<t)t((<i(>s arc vontlncntal ishoids, 

 originated throuf/h stihsidcm-e;'''' they M formed at a past period one 

 large island, and this island itself was at a still former period ''in con- 

 nection with the Amerii'an continent." This is in direct opposition 

 to the opinions of ''Darwin, Hooker, Salvin, (Jrisebach, Englar, M. 

 Wagner, Wallace, Peschel, and later by Wolf, and Agassiz, as herein 

 (pioted. All declare that these islands are of recent volcanic origin, 

 that they have emerged out of the sea through volcanic activity, and 

 have bec(miepeoi)led from the continent," etc. '• Henri :\Iilne Edwards 

 alone holds a different opinion; he believes that the (ialapagos repre- 

 sent the remains of a former continent, and in this opinion I agree." 

 He then proceeds by saying that "the principal reason of the be- 

 lievers of the elevation theory is the volcanic condition of the islands. 

 i>ut 1 do not see any dillliculty in that. If mountain ranges like the 

 Himalayas, the Alps, the Andes, the liocky Mountains, could be ele- 

 vated tlnmsands and thousands of feet, why eould not subsidence take 

 place in other places? If Central America should disappear by and by 

 through subsidence, the result would be that the tops of the highest 

 mountains wonld form volcanic islands, some with still active volca- 

 noes. This W(mld be exactly the condition we see to-day in the (iala- 

 pagos. I think, therefore, that the volcanic nature of a group of islands 

 is no positive proof of its recent origin. Such groups of islands can 

 be Just as well considered as forme<l of the tops ot the volcanic moun- 

 tains of a sunken part of a continent." * * * 



" I believe, therefore, that the peculiar genera we tind to day on the 

 C»alai)agoshave not originated there, but have been preserved in their 

 old condition.'' * 



Dr. Ham- in Am. Naturalist, April, 1891. 



