Association of American Geologists and Naturalists. 125 



and in the wide space between it and the low islands of Polynesia, is 

 to be attributed to the prevalence of cold currents, which proceeding 



northward from the polar regions are perceptible the whole distance 

 from Cape Horn to Callao, and I presume much further to the north, in 

 a temperature of. the ocean too low for the existence of the coral ani- 

 mals, and that in a similar low temperature we are to seek for the cause 

 of their absence at the Cape Verd Islands"* and the other islands de. 

 signaled m my article as destitute of coral formations. 



That I have never intended to claim more than is here set forth, is I 

 think manifest in the following extracts ; and if I have been otherwise 

 understood, the error is wholly attributable to my having defectively ex- 

 pressed ideas perfectly clear to my own mind, and thereby misled my 

 readers. J J 



"It appears to me, that such coincidences as the facts here submitted 

 prove to exist, between certain temperatures of the ocean and the ab- 

 sence or presence of coral reefs, can scarcely be considered by any 

 ft ecting mind as merely casual ; and that there are strong grounds for 

 e ieving that we have here a clue to the real cause of the singular ab- 



recent coral formations in certain regions corresponding in 



sraZ,. j § SaVe tem P erature to those wh ere they are most profusely 



In order to enable us, however, satisfactorily to determine 



ess • heir geo § ra P hical distribution is affected by such causes, it is 

 vJi that We shouId be furnished with a connected series of obser- 

 alon "I " oceanic temperatures at the surface and to certain depths, 

 and"a ^^ ° f tHe African continent, the coasts of Australia, and 

 *at of 10 ^ the C ° ral archi P ela g° s of tne Indian seas, together with 



sr>h ° v? Seas be y° nd the limits of such formations, in both hemi- 

 spheres."! 



"Whil 

 "ere off' & C ° nvinced m m y own mind of the truth of the suggestions 



p T r " n regard t0 m e absence of coral formations in certain re- 



certai' 1 ^ COnsc ' ous a,so that the data upon which they rest, though 



b Qt jj . y P resen ting a strong case as far as they extend, are after all 



*hat Jh m com P aris °n with those still deficient. I submit them for 



servat' ^ Wor,M - What this may be, time and more extensive ob- 



rati 0n T mUSt delermin e. Claiming only to have at least sought a more 



that f °^ accoun ting for the peculiarities here pointed out, than 



s "ow th U ^ os,n S tnem altogether fortuitous, I shall rejoice if the end 



of v i Ve cont ributed in the slightest degree or in a single point 



c °rdino- a d v ancement of the great object to which we are all, ac- 



S t0 ou r opportunities, devoted. 1 '!: 



scattered 

 howfi 



* It 



°*' J ° Ur - Nat - Hist., Vol. IV, pp. 159, 160. t lb. p. 162. t lb. p. 162. 



