March 25, 1898. ] 



SCIENCE. 



415 



leaving tlie upper basin free. Thence to the 

 Gulf it followed the western back swamps, 

 the main river not overflowing below Vicks- 

 burg. The safety of the upper Yazoo basin 

 resulted not alone from the high ground 

 along the Mississippi, but also from the belt 

 of high unfloodable ground that divides the 

 upper Yazoo and the Sunflower basins. 

 This belt is mentioned in the text as an ex- 

 tension of Crowley's ridge (on the west side 

 of the Mississippi, above Helena). It is 

 truly in line with Crowley's ridge, but the 

 two are probably of altogether different 

 origins. Crowley's ridge is an isolated part 

 of the uplands that border the flood plain 

 on the west (see Science, I., 1895, 605) ; but 

 the unfloodable belt between the Yazoo and 

 the Sunflower probably marks a former ag- 

 graded path of the Mississippi, deserted at 

 the time of some ancient flood. 



THE FIJI COEAL REEFS. 



A LETTER from Alexander Agassiz, on 

 ' The Islands and Coral Eeefs of the Fij i 

 Group' {Amer. Journ. Sci., V., 1898, 113- 

 123), presents matter of much importance 

 in connection with theories of reef forma- 

 tion. Instead of finding, as was expected 

 from the accounts by Darwin and Dana, 

 that a progressive subsidence would ac- 

 count for the barrier reefs of the Fiji group, 

 numerous elevated reefs were seen at heights 

 of 600 to 800 feet ; and a number of barrier 

 reefs and atolls were discovered to be only 

 the denuded remnants of reefs formerly 

 elevated. Boring into the reefs was re- 

 garded as unnecessary, for the natural sec- 

 tions exposed by the elevated reefs revealed 

 their structure clearly. While the elevated 

 reef deposits may have been formed during 

 a period of subsidence, that movement can- 

 not be included in the present geological 

 period, nor can it account for the existing 

 distribution of reefs at sea-level, whei-e re- 

 cent coral growth is thought to have added 

 only a relatively thin crust to a pre-existent 



mass. A possible relation of circular or 

 oval atolls to a^ foundation upon the worn- 

 down rirh of a large volcanic crater (caldera) 

 is suggested ; calderas being of frequent oc- 

 currence, and having outlines and dimen- 

 sions similar to those of reefs near by. 



The separation of the smaller volcanic 

 islands from the larger ones in the Fiji 

 group is taken as evidence of long contin- 

 ued denudation, largely by the sea, after 

 the uplift of the region. The possibility 

 of some of this separation being due to sub- 

 sidence is not explicitly considered. The 

 importance of subsidence in the formation 

 of reef deposits may still be maintained, 

 but in the Fiji group it seems to have little 

 bearing on present reef outlines. 



THE MAZAMAS. 



The Mazamas, a society of practical 

 mountaineers organized on the summit of 

 Mt. Hood, in July, 1894, hold their annual 

 meetings on mountain tops and publish their 

 proceedings in ' Mazama, a record of moun- 

 taineering in the Pacific Northwest ' (Port- 

 land, Oregon) ; numbers for 1896 and 1897 

 having been issued. The second is the 

 Crater Lake number, which gives a most 

 enjoyable account of the gathering there in 

 1896, already noted in Science (June 18, 

 1897). Essays on the discovery, geography, 

 geology, botany, zoology and bibliography 

 of Crater Lake, with many illustrations 

 from photographs, make this number of 

 high value, deserving of earlier mention 

 than in this belated note. 



W. M. Davis. 



CURRENT NOTES ON 3IETE0R0L0GY. 



METEOROLOGICAL OBSERVATIONS DURING THE 



ECLIPSE OF JANUARY 22. 



The meteorological observations made at 

 Viziadurg during the eclipse of January 

 22d, as noted by Mr. J. Eliot, Meteorolog- 

 ical Esporter to the Government of India, 



