On the Distribution of the Superficial Detritti^ dftTitjitps. W^ 



Oblique Lemnoid and retrogressive Syphonoid. 



S. M. Drach. 



June 20, 1849. 



'\ LXXVI. On the Distribution of the Supeijicial Detritus of the 

 Alps, as compared with that of Northern Europe. By Sir 

 Roderick Impey Murchison, F.R.S., V.P.G.S. Sfc; 

 Mem. Imp. Ac. Sciences of St. Petersburgh, Corresp. Member 

 of the Academies of Paris, Berlin, Turin, Sfc* 



REFERRING to his previous memoir upon the whole structure 

 of the Alps and the changes which those mountains underwent, 

 the author calls attention to the fact, that whilst during the forma- 

 tion of the molasse and nagelfiue a warm climate prevailed, so after 

 the upheaval of these rocks an entire change took place, as proved 

 by the uplifted edges of these 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 so clearly expounding the laws 

 which regulate the movement of these bodies; Sir Roderick conceives, 

 that the physical phsenomena of the Alps and Jura compel the 

 geologist to restrict the former extension of the Alpine glaciers 

 within infinitely less bounds than have been assigned to them by 

 those authors. True old glacier moraines may, he thinks, be always / 

 distinguished, on the one hand, from the ancient alluvia, and on the 

 other from tumultuous accumulations of gravel, boulders and far 



* Abstract of a Memoir read before the Geological Society May 30, 1 849, \ 

 when His Royal Highness Prince Albert honoured the meeting with his" 

 presence for the first time as a Fellow of the Society. 



