IXXX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



the brown-coal generally as a marine deposit, and to have been 

 occasioned by the heaping together of drift-wood on the sandy bottoms 

 of the ancient seas, and does not admit that any great change of 

 level took place between the cretaceous and tertiary deposits. Next 

 in importance is the Septaria-clay, with its numerous fossils, over- 

 laid by diluvial deposits ; these the author divides into northern and 

 southern formations. 



The third portion of the work is occupied with the geological de- 

 scription of particular districts. 



Prof. Girard has also published during the past year another work 

 entitled * Geological Wanderings.' It consists of a series of letters 

 written in the preceding year, in which he has described some of the 

 chief geological features of parts of Switzerland, particularly the 

 Valais and neighbouring districts ; the Vivarais and its older rocks, 

 basalts, and volcanoes ; and finally, the Velay and Le Puy, in which 

 many of the pheenomena connected with the igneous and plutonic 

 rocks of that interesting district are described and analysed. One of 

 the author's chief objects in the Velay was to inquire into the extent 

 and origin of the basalts, and he found there, as in the Vivarais, that 

 these rocks were much older than the volcanos, and that they were 

 entirely independent of them ; he also found that the volcanic moun- 

 tains of the Velay consisted solely of scoriaceous outbursts, and that 

 no lava-stream had flowed from them ; in this respect confirming 

 the observations of former travellers. 



Dr. Guido Sandberger of Wiesbaden has recently published in the 

 * Journal of the Nassau Society for Natural History,' an account of 

 the first discovery of a species of Clymenia in the Cypridina-slates 

 of the Devonian system, near Weilburg in Nassau. For many years 

 Dr. Sandberger and his brother had in vain sought throughout this 

 formation, and particularly in the limestone-masses contained in the 

 Cypridina-slates, for the genus. This discovery is the more interest- 

 ing, as it confirms the identity of this deposit with the Cypridina- 

 slates of other districts. 



One species only has as yet been found in Nassau, and that is 

 new ; the name of Clymenia subnautilina has been given to it. The 

 genus Clymenia was originally proposed by Count Miinster, and 

 we are already indebted to Dr. G. Sandberger for a notice in the 

 'Bulletin de la Societe Imperiale des Naturalistes de Moscou' of 1853, 

 giving an account of the nature and characteristics of Clymenia and the 

 allied form of Goniatites. Some interesting remarks on the analogies 

 between these two genera, by Dr. Sandberger, will also be found in his 

 memoir on the " Organization of Goniatites," in the * Journal of the 

 Nassau Society for Natural History,' 1851. In the notice under 

 consideration, the author alludes to the measurement of the thick- 

 ness of the whorls of this species of Clymenia by means of the Lep- 

 tometer, an instrument invented by himself for the purpose of mea- 

 suring thin bodies, which could not be got at by any ordinary ruler or 

 compasses. He observes in a recent communication that he has given 

 it this name (from XcTrros, thin), on account of its being adapted to mea- 

 sure the thickness, slope, and taperness of all possible minute and thin 



