VIII. On a Portion of the Tertiary Formations of Switzerland. By 

 D. T. Ansted, Esq. M.A., Fellow of Jesus College. Fellow of 

 the Society and of the Geological Society ; Professor of Geology 

 in King's College, London. 



[Read May 20, 1839.] 



The Tertiary formations of Switzerland are singularly deficient in 

 most of those points which have rendered the contemporaneous deposits in 

 other countries of Europe so attractive and important. The beds, for the 

 most part, vary Jbut little in mineral structure : they seem to have been 

 accumulated rapidly, and under circumstances little favourable to the 

 preservation of organic remains, and the few fossils that are known to 

 occur, possess none of that definite character, which elsewhere indicates 

 with sufficient clearness to what well-known group the one in question 

 was anterior, and what beds were anterior to it. Owing, perhaps, to this 

 want of determinate character, and partly, also, no doubt, to the superior 

 interest of the strangely contorted secondary beds, which form the 

 principal mass of the great mountain district always within sight, it 

 has happened that travellers in general have neglected to examine care- 

 fully the great valley of Switzerland, and I am not aware of any detailed 

 account in our own language of so considerable a portion of European 

 Tertiary Geology. 



I am not able, indeed, myself to add much to the small amount of 

 our knowledge on this subject, but anxious at all events to direct atten- 

 tion to it, I have ventured to lay before the Society a few observations 

 made during a stay of several weeks at Lausanne, in the summer of 1838. 

 In order to do this most effectually, I shall first consider the nature of 



