104- Prof. Sedgwick and Mr. Murchison on the 



Our examination of the calcareous zone on the south flank 

 of the Alps was much too hasty to enable us to establish the 

 three subdivisions we are now attempting to illustrate. We be- 

 lieve however that they may be traced, and that the zone may in 

 many places be distinctly divided into older Alpine limestone 

 and younger Alpine limestone, separated from each other by a 

 system of strata composed of thin-bedded limestone, alternating 

 with shales, gypseous marls, &c. One or two sections, kindly 

 shown to us by Professor Rippl, exhibited this succession: 

 and if these gypseous marls be considered as the representa- 

 tives (in a somewhat altered form) of the saliferous system of 

 the northern Alps, the subdivisions of the two great calca- 

 reous zones will be in perfect accordance. 



In the southern Italian Alps, the younger formation of lime- 

 stone has been examined with great care by MM. Maraschini 

 and Catullo; and the latter gentleman has, by the help of a 

 great suite of organic remains, proved the existence of beds of 

 the age of the green-sand, overlying rocks containing many 

 organic remains of the oolitic series. Near Belluno, Feltri, 

 Canal di Brenta, &c, the system terminates in a red and 

 white fissile limestone (scaglia) containing many flints ; which, 

 from its structure, position, and fossils, has been indentified 

 with the chalk. 



Between Adelsberg and Trieste the limestone beds contain 

 many fossils, and among them are innumerable Nummulites. 

 How far these fossils descend in the secondary series, we are 

 not able to determine. In the ascending order, the forma- 

 tions, before they reach the Adriatic, undergo a great change 

 in external character. The calcareous beds (chiefly composed 

 of a compact, light-gray limestone full of Nummulites) no 

 longer predominate ; but become subordinate to great masses of 

 blueish gray micaceous shale, and of sandstone generally of a 

 gray or greenish gray colour, and here and there containing 

 a few traces of carbonaceous matter. Along the shores of the 

 Adriatic, for several leagues south of Trieste, the micaceous 

 shale is so abundant as to produce a succession of ruinous 

 cliffs, apparently held together only by the subordinate bands 

 of sandstone and nummulite-limestone. We believe that this 

 system is now generally regarded as the representative of the 

 green-sand or chalk — a conclusion which is in perfect accord- 

 ance with our views of the structure of the district. 



It is not our intention, in such a sketch as this, to attempt 

 any detailed description of the younger secondary formations 

 of the Austro-Bavarian Alps ; we must, however, notice some 

 of their varieties of structure, and some of the masses which 

 are subordinate to them. Occasionally they pass into dolo- 

 mites, 



