53 8 THE POPULAR SCIENCE MONTHLY. 



mon ones of lava, others of flint or obsidian. They were acquainted 

 with gold and probably with copper, but those metals were rare with 

 them. Woods were abundant, although there now exists only a single 

 tree, a kind of palm, in all the archipelago. The vine, which is now 

 cultivated almost exclusively, seems to have been unknown at that pe- 

 riod. 



The islands of Thera, Therasia, and Aspronisi are the remains of a 

 laro-e island which existed before the formation of the bay. Their 

 soil is composed of three classes of rocks : metamorpkic rocks (marbles 

 and mica-schists), volcanic rocks of subaerial formation, and volcanic 

 rocks of submarine formation. Volcanic products of subaerial forma- 

 tion are the only ones in view in the larger part of the group. They 

 appear as compact lavas, scoriae, pumice, and in dikes. Fragments of 

 the rocks in the dikes have been subjected to examination like that 

 which was given to the lavas of the recent eruption, and the study has 

 been applied to the solution of the problem of the specification of the 

 triclinic feldspars. By it M. Fouque has been led to conclude that the 

 four varieties so described are distinct. 



M. Fouque accounts for the origin of Santorin by supposing that 

 there was an island composed of marbles and mica-schists, against 

 which submarine eruptions took place ; a considerable upheaval then 

 occurred. The eruptions having become subaerial, masses of matter 

 were thrown out from different vents, and produced a large island, the 

 slopes of which became wooded and its valleys fertile, while its sum- 

 mits continued to be rugged with lavas. A violent convulsion, ac- 

 companied and followed by formidable explosions and showers of 

 pumice, hollowed out the bay. Finally, eruptions which have taken 

 place since the beginning of the historical period have produced the 

 Kamenis. 



The phenomena of this volcano, which is one of those that were 

 cited by Leopold von Buch, the principal advocate of the theory, as 

 examples of the mode of formation which he suggested, have been 

 carefully studied in view of their bearing upon the theory of craters 

 of elevation. They appear, in the light of M. Fouque's investigations, 

 to contradict this theory at every point, to sustain the old arguments 

 which have been brought against it, and to offer other features which 

 are irreconcilable with it ; so that the conclusion is reached that the 

 theory must be definitively abandoned. Revue Scientifique. 



