350 SOCIETY OF PHYSICS AND NATURAL HISTORY, OF GENEVA. 



situated in different parts of the earth, does not prove them to be of the 

 same age. The term geological epoch, which always implies some dis- 

 tinction in the flora and in the fanna, in reference to other ei^ochs, 

 is, therefore, not adapted to the scientific signitication for which it 

 is intended. The above-mentioned idea is being more and more intro- 

 duced into science. 



Professeur D. Colladon has placed before the society some beauti- 

 ful photographs, which represent cuttings of tbe earth upon the hill of 

 Geneva, executed upon the Tranchees, a hill which is believed to be a 

 product of the ancient alluvion of the river Arve. He published in 

 1870, in the Archives, (vol. VXXIX, page 199,) an extended notice upoa 

 this subject, and also drew attention to the study of the terraces of the 

 southern shore of Lake Leman. 



M. Ernest Favre has presented an interesting communication on the 

 geology of the mountains of the region southwest of the canton of 

 Fribourg, composing the chain of the Nivemont, the Moleson, the 

 Yerreaux, and tliat of Saint Cray; he compared the strncture of this 

 solid mass with similar formations, which have been observed in the 

 Tyrol and in the Carpathes. (This has appeared in the Archives.) 



Finally Professor Thury has measured the thickness of the section 

 of the glacier of the Oldenhorn, such as it presents from the lake of 

 Eheto. He estimates it at 45 meters, and has counted from 70 to 80 

 horizontal strata, each one having a thickness of about 60 decimeters. 



Botany. — Since the works of Darwin have attracted the attention of 

 naturalists to the question of the origin of organic species, their desceat 

 and their affiliations, the manner of distribution of these species over 

 the surface of the globe, which has great interest on the bearing of this 

 question, has been studied with more attention than in the past, and is 

 becoming every day the object of new and im]^ortant researches. M de 

 Candolle has shown that botanists have found in the flora of the 

 Fortunate Islands hardly any plant similar to the western coast of 

 Africa, while they contain a large number in common with those of 

 Europe. This fact would indicate that the islands in question have been 

 formerly united to Europe, by a terrestrial communication, while it 

 seems to have always remained separated from Africa. It is true we 

 are by no means certain of the flora of the high mountains of Maroe, 

 which throws some doubt upon the conclusions we would be inclined to 

 infer from the above observations. 



Dr. Miiller contributed an article, accompanied with drawings, upon a 

 new species of hair discoveredupon two Asiatic plantsofthecombretacious 

 family. These hairs have the general appearance of scales or the plates of 

 a shield, but instead of exhibiting a disk formed of numerous cells en- 

 tirely radial, they are formed of a regular net-work of cells, which is 

 only one cell in thickness, like the ordinary' leaf of mosses. Dr. Miiller 

 described these curious scales and proposed to give the name of Lepide 

 riticuUe. 



