1880 .] Correspondence. 601 
Earth exadtly representing its elevation elsewhere. (See “ Con- 
stitution of the Earth,” pp. 286, 287.) I am pleased to learn, 
from the abstract of a paper read at the Royal Society of Edin- 
burgh by Mr. John Murray, and published in “ Nature ” of 
August 12th inst., that this seems to be the conclusion arrived 
at by scientific members of the Challenger Expedition. The 
objedt of the paper is “ to show, first , that while it must be 
granted as generally true that reef-forming species of coral do 
not live at a depth greater than 30 or 40 fathoms, yet that there 
are other agencies at work in the tropical oceanic regions by 
which submarine elevations may be built up from very great 
depths, so as to form a foundation for coral reefs ; second , that 
while it must be granted that the surface of the Earth has under- 
gone many oscillations in recent geological times, yet that all 
the chief features of coral reefs and islands can be accounted for 
without calling in the aid of great and general subsidences.” — 
I am, &c., 
August 18, 1880. 
Robt. Ward. 
