82 Prof. Sedgwick and Mr. Murchison on the 



class, has been finally referred to the age of the lias. Number- 

 less strata, formerly described as primitive or transition, have 

 also been successfully compared with the green-sand and the 

 newer secondary formations. These discoveries belong to the 

 recent history of geology*. Many new and careful observa- 

 tions must, however, be made before the great deposits of the 

 Alps can be brought into a rigid comparison with the secon- 

 dary formations of the North of France, of the North of 

 Germany, and of the British Isles. The peculiar mineral 

 structure of the Alpine limestone — the great mountain masses 

 of it, so modified by crystallinepower as to lose the traces of 

 depository origin — the frequent absence of organic remains, 

 and of those well-defined beds of clay and sandstone which 

 form the best subdivisions of the English secondary groups — 

 the enormous faults and dislocations produced during the dif- 

 ferent epochs of elevation — all these causes have greatly ob- 

 scured the minuter subdivisions of the different systems of 

 the chain : so that in the Geological Map of Germany (only 

 finished last year, under the superintendence of one of the 

 greatest naturalists of Europe) nearly the whole of the secon- 

 dary calcareous zones are still represented by one colour, and 

 described as the Calcaire indetermine des Alpes-\. Under these 

 circumstances we have ventured to throw into a connected 

 point of view our own observations, made in the summer of 

 1829 during several traverses among the eastern parts of the 

 chain. We offer them as nothing more than an imperfect 

 sketch, filled up in some instances by materials derived from 

 others: we are anxious to state matters of fact correctly; and 

 we wish that in every instance they should be carefully se- 

 parated from any theoretical conclusions we may have derived 

 from them. 



The following are the principal directions in which we made 

 traverses through the eastern portions of the Alps. 1st, From 

 Vienna to Gratz over the Somring : 2nd, From Gratz to Lay- 

 bach, over a portion of the primary axis and the southern cal- 

 careous zone : 3rd, From Laybach to Capo dTstria, over the 

 calcareous chain, which is a prolongation of the Julian Alps, 

 and forms the water-shed between the basin of the Danube 

 and the Adriatic : 4th, A complete traverse by the gorges of 

 the Tagliamento and the crests of the Tauern Alp to the 

 valleys of Salzburg: 5th, Through the lateral valleys of the 

 northern calcareous zone between Salzburg and Inspruck : 

 6th, Across the calcareous zone by the Seefeld pass to the 



* We here refer to various memoirs of MM. Elie de Beaumont, Boue, 

 &c. &c. 

 f Geological Map of Germany, published by S. Schropp and Co., Berlin. 



plains 



