154 Professor Hausman on the Geognostical Structure 
essay on the geognostical structure of the Appennines, of which 
he has transmitted to us a short abstract, the substance of which 
we shall now lay before our readers. The first section of the essay 
contains an account of the physiognomy of the mountains, moun- 
tain ranges, and valleys. The second , and by far the most extensive 
and important section, treats of the internal structure of the Ap- 
pennine chain. The greater part of it displays a wonderful unifor- 
mity, the predominating rock being a white compact limestone, 
which shews the same characters in places the most distant from 
each other. But this uniformity of structure is interrupted in 
the upper part of the chain, where it is connected with the Alps, 
and in its southern part in Calabria, where there are consider- 
able displays of older rocks. The lateral chains, in many places, 
and to a considerable extent on both sides of the great chain, ex- 
hibit considerable variety in internal structure and composition ; 
and, hence it is, that transverse sections of the Appennines often 
display numerous alternations of various rocks ; but it differs from 
many other ranges in this respect, that the oldest formations in 
those places where they appear along with the newer ones, occur 
neither in the central parts of the principal chain, nor in the 
higher parts of those, but on the sides and in comparatively low 
situations. 
No primitive rocks occur in the middle part of the Appen- 
nines, their place being taken by those of the transition class. 
Our author does not give any decided opinion as to the formation 
of the granite and gneiss met with in some places at a distance 
from the central chain, as in Tuscany, and in the islands of 
Giglio and Elba. Granite, gneiss and mica- slate are pretty 
widely distributed in South-western Calabria, and in the oppo- 
site coast of Sicily, and these appear to belong to the primitive 
class. 
The transition formation is not only very widely distributed 
in Italy, but it also abounds in various subordinate members, 
some of which are remarkable on account of their structure and 
rarity. The Appennines of Genoa, Lucca, Modena, and a part 
of Tuscany, are composed of them. In the southern part of 
Tuscany, the transition rocks extend from the border of the 
principal mountain-chain to the hilly land of Sienna, and to the 
sea coast; and the neighbouring islands are partly composed of 
