Deoebibeb 37, 1895.] 



SCIENCE. 



887 



sank down in a few hours. A lighthouse 

 built in 1873 at a cost of $40,000 was 

 undermined and fell in 18S2; it was re- 

 built a mile inland, but in 1888 was re- 

 moved two miles further east. The winds 

 cause a continual change in the form of 

 the sand dunes. Landmarks are thus 

 blown away ; hollows and ponds replace 

 hills, and breaches in the sod near the few 

 houses are carefully repaired to prevent the 

 thin soil from being blown away. Wild 

 horses of a small and hardy breed roam 

 over the island in separate herds, each led 

 by an old male. They numbered about 300 

 in 1828 ; 400 in 1864 ; 150 to 250 now. 

 Their numbers have sometimes decreased 

 by starvation caused by the burial of pas- 

 turage under the drifting sand ; and they 

 have not infrequently been eaten by the 

 inhabitants. The unbalanced condition of 

 the smaller imported fauna is curiously 

 illustrated. English rabbits were intro- 

 duced at one time and soon overran the 

 island ; but they were exterminated by rats 

 that came ashore from some vessel. The 

 government then sent cats to the island, 

 and these, after extinguishing the rats, be- 

 came so numerous that dogs and shot guns 

 were brought to destroy them. Rabbits 

 were then imported once more, and again 

 became numerous ; but were exterminated 

 a second time by snowy owls. 



The absence of ledges and boulders sug- 

 gests that this strip of loose sand is only the 

 vanishing remnant of a long bar, formed 

 by wash from some larger island of glacial 

 drift, now destroyed. 



THE PHYSICAL FEATURES OF MAURITIUS. 



' The physical features and geology of 

 Mauritius ' are described by H. deH. Haig 

 ( Quart. Journ. Geol. Soc, Loudon, li, 1895, 

 463-471). In crossing the lava slopes of 

 the island, one comes without warning on 

 immense ravines, worn to depths of over a 

 thousand feet by the rapid streams, fed by 



the moist trade winds. There are few lakes; 

 two occur in old craters, besides various 

 shore lagoons and many marshes and pools 

 among the newer lava beds. Long caves 

 leading underground streams are very com- 

 mon in the fresh lavas. One extensive 

 tubular cavern in solid lava, like a great 

 railway tunnel, measured thirty feet in 

 width and height, and was followed for a 

 mile and a half without reaching its end ; 

 bubbly lava drops remain on its roof and 

 walls. The writer accepts the current ex- 

 planation that these caves are caused by 

 the continued iiow of the still molten cen- 

 tral part of a lava stream after the surface 

 has hardened and after the supply from 

 above has ceased. Where cavern roofs 

 have partly fallen in, the remnants form 

 natural bridges, of which there are many 

 examples. The most remarkable old cav- 

 ern now appears as a strange dry ravine, a 

 mile and a half in length, with vertical 

 walls eighty feet high ; the roof, having for 

 the most part fallen in bodily, now lies on 

 the floor of the ravine, where the ripple- 

 marked lava surface maj^ still be seen ; but 

 every few hundred yards parts of the roof 

 still remain as bridges. In one case a cav- 

 ern roof was burst upward by the rise of 

 its torrent, fed by the heavy rainfall of the 

 hurricane of February, 1876. 



W. M. Davis. 



Harvard University. 



CURRENT NOTES ON ANTHROPOLOGY (XriL). 

 THE CRADLE OF MAYAN CULTURE. 



The results of Mr. Mercer's explorations 

 of the caves of Yucatan (see Science, p. 

 766) corroborate in a noteworthy manner 

 the studies of the Mayan MSS. and art 

 relics. The cave-hunters discovered no 

 trace of a culture lower than that of the 

 historic Mayas. These, therefore, came 

 into the peninsula already semi-civilized. 

 The acute analyst of Mayan art. Dr. P. 

 Schellhas reached some years ago the same 



