1849.] MURCHISON ON THE DETRITUS OF THE ALPS. 65 



species, to which the above name may be given from its most remark- 

 able character. 



The true nature of these remains seems still rather uncertain. 

 Schlotheim described them as Orthoceratites, and in his figure a 

 central siphon is represented, and the stem seems composed of di- 

 stinct cups or joints*. No indication of either of these characters is 

 seen in the most perfect of our specimens, so that we almost doubt 

 whether his fossil belongs to the same class. Other geologists have 

 described them as fucoids. In the ^Silurian System' they are classed 

 as Polyparia, which seems now the opinion generally received. Some 

 of our specimens have left merely a dark, perhaps carbonaceous im- 

 pression on the slate ; others show a cartilaginous or horny texture. 

 In several specimens the slate is discoloured for some distance on 

 each side, and shows minute scales of carbonate of lime, as if the more 

 perishable parts of the animal had extended thus far. It is thus 

 doubtful whether these remains have all belonged to animals of one 

 class ; and whether some of them may not rather have been internal 

 organs, than the external axis of a variety of polypifer ? 



May 30, 1849. 



P. Martin Duncan, Esq., M.D., and J. Lane Oldham, Esq., were 

 elected Fellows of the Society. 



The following communication was then read : — 



On the Distribution of the Superficial Betritus of the Alps, as com- 

 pared with that of Northern Europe. By Sir Roderick 

 Impey Murchison, F.R.S. G.S. L.S., Hon. Mem. R.S. Ed., R.I. 

 Ac, Mem. Imp. Ac. Sc. St. Pet., Corr. Mem. Ac. France, Berlin, 

 Turin, &c. &c. 



[Abstract.] 



Referring to his previous memoir upon the structure of the 

 Alps and the changes which those mountains underwent, the author 

 calls attention to the fact, that as during the formation of the molasse 

 and nagelflue a warmer climate prevailed, so after the upheaval of 

 those rocks an entire change took place, as proved by the uplifted 

 edges of such tertiary accumulations being surmounted by vast 

 masses of horizontally-stratified alluvia, the forms of whose materials 

 testify that they were deposited under water. The warm period, in 

 short, had passed away and the pine had replaced the palm upon the 

 adjacent lands, before a glacier was formed in the Alps or a single 

 erratic block was translated. 



Though awarding great praise to the labours of Venetz, Charpen- 

 tier and Agassiz, which have shed much light on glaciers, and par- 

 ticularly to the work of Forbes for clearly expounding the laws which 



* Petrefactenkunde, Nachtrage, p. 56, tab. 8. fig. 3. 

 VOL. VI. part I. F 



