270 Dr. Mae Culloch on the 
origin. They comprise numerous marine objects, consisting of 
shells and fishes; but these are far more abundant in the marl 
than in the sand, while very extensive tracts of alluvia are 
found without any. The shells are said to be sometimes similar 
in both beds; but it is very important to remark, that where 
they abound, they are found associated in families; a proof 
that they have not been transported, but that they now lie 
where they were originally produced. 
Some of these animals, it must now be observed, are 
admitted to exist in the present seas of Italy, while others are 
supposed to be exotic or else unknown. Thus a great deal of 
additional obscurity has been introduced into this subject, 
which it is important to remove. As I cannot here however go 
into any great length of detail in this point, I must content 
myself with the case of Monte Bolca, as the most conspicuous 
example of erroneous observation and reasoning. 
In this hill, the fishes are found in a marly slate, which is 
part of the lowest or marine bed, called by Brocchi subapennine. 
This substance does not lie in continuous strata, but in distinct 
and detached masses among the looser materials. The forms 
of these animals are well defined, particularly in the harder 
parts. The animal matter is indurated and mixed with the 
including earth, is of a brown colour, and is further, at times, 
so thick as to project from the stone, and to admit of being 
separated. This part is brittle and glossy, so as somewhat to 
resemble glue, but the bones ‘are sometimes converted into ¢al- 
careous spar. 
With respect to the species, Volta, with a very imperfect 
knowledge of ichthyology, has thought fit to give names to one 
hundred and five, and has performed this task most incorrectly. 
Moreover, prejudiced in favour of some marvellous and myste- 
rious revolutions of the globe, and like many other geologists, 
preferring an impossible solution to an obvious one, he has 
referred his imaginary species to various distant places of birth 
or habitation. Thus he begins by pointing out seven fresh- 
water fishes, as if he had not created difficulties enough without 
that; whereas Blainville, with an accurate knowledge of this 
