of Serpentine f Sfc. in the Apennines. 163 



Sdly. To the confusion that has reigned, from the want of 

 a good mineralogica! determination, between the rocks with 

 a serpentine base of different formations. 



3dly. To the structure of the serpentines (ophiolites), 

 in mass, which often occur as isolated mountains without 

 distinct stratification, without foreign characteristic bodies, 

 &c. 



It certainly required this union of unfavorable circum- 

 stances to conceal the true position of these rocks from the 

 »obser?ation of geologists distinguished for their science, their 

 activity, and their works, who have before me travelled 

 over that part of the Apennines, where I have with certainty 

 observed the position of these rocks. I have at the same 

 time acquired new proofs of the presence of rocks as per- 

 fectly crystallized as granite, placed on aggregate rocks as 

 coarse as sandstone, on rocks perfectly resembling those 

 which, in the same canton, contain organic remains. The 

 facts I am about to expose Avill prove these two results, and 

 the quotations I shall bring forward will shew that they were 

 not only neither well known nor generally admitted, but 

 that persons have often been deceived with respect to them* 



Article 1. 



Enumeration and designation of the principal rocks 

 composing that part of the Apennines which forms 

 the subject of this memoir. 



Those parts of the Apenniaes which are situated between 

 Genoa and the north of Florence, and the environs of Sienna, 

 not comprising the hills that border the Mediterranean, pre- 

 sent three kinds of principal formations, which we shall 

 designate by the following names, without considering. In 

 this enumeration, the order in which they occur. 



1st. The sandy, marly and shelly formation (terrain sablo- 

 marneux-coquillier), or tertiary formation of Brocchi and 

 almost all geologists. 



l2 



