Professor Hausmann on the Geology of the Apennines. 281 



These observations do not exhibit any uniform regularity 

 in the relative situation of the transition rocks of the Apen- 

 nines ; but they are most probably to be referred to one epoch. 

 The direction and inclination of the strata are very various. 

 Prof. H. thinks it not improbable that these rocks are a con- 

 tinuation of the secondary formations of the Alps. 



After remarking that the upper Apennines exhibit a more 

 varied structure than the other parts, Prof. Hausmann pro- 

 ceeds to describe the rocks between Tuscany and southern 

 Calabria. The compact limestone already noticed, consti- 

 tutes the most prominent geological feature, and is stated 

 to resemble the white Jura limestone, It does not contain 

 beds of oolite, which are often met with in the latter, but 

 calcareous and argillaceous marl and hornstone. Professor 

 Hausmann observes that it is difficult to decide whether the 

 limestone of the Appennines is to be referred to the newest 

 secondary formations, to which the Jura limestone belongs, 

 as there are no super- incumbent formations, nor petrifactions 

 sufficient to determine the question. The transitions and al- 

 ternations of the strata increase the difficulty. From various 

 considerations, however, he is inclined to refer the principal 

 part of this limestone to the same formation as the Jura 

 limestone. If this opinion is correct, the lower part of the 

 plain of the Po with the Adriatic sea, is to be considered as 

 a longitudinal valley extending from N.W. to S.E. in this 

 limestone formation. The principal boundaries of the for- 

 mations have the same direction, with some little interruption. 

 The continuation of the line of the white limestone of the 

 Apennines above Bologna, towards the N.W., is found near 

 Arona, in the same limestone. The line of the transition 

 mountains, which begins in Calabria, skirts cape Circeo, 

 and with increasing breadth stretches through the southern 

 part of Tuscany to the upper Apennines, and thence to 

 the Alps. The primitive rocks begin in the southern extremity 

 of Calabria, and in Sicily, touching either the granite of Giglia 

 and Elba, or, if this rock belongs to the transition formation, 

 probably the primitive rocks of cape Corso in Corsica. 



The tertiary mountains are next described, and, for the 

 most part, are so completely separated from the Apennine 

 limestone, that no transition can be discovered. There are, 

 however, some exceptions in the territory of Otranto, where 

 a transition was first noticed by Brocchi. 



The tertiary formations are distinguished by Professor 

 Hausmann into more general and more local. 



The more general consist of argillaceous marl, passing on 

 one side into slate-clay, and on the other into sandstone; 



Vol. 63. No. 312. April 1824. N n plastic 



