GEOLOGICAL HISTORY OF SERPENTINES. 181 
studies of Taramelli on the Italian serpentines, pp. 80-128. It is impossible to speak too 
highly of the zeal, the industry and the scientific spirit exhibited by the Italian geologists 
in these researches undertaken for the solution of the great question of the ophiolites, 
which may well be held up asa brilliant example to be followed by other nations in similar 
circumstances. 
§ 45. Mention should also be made of the brief memoir of thirteen pages, in the French 
language, by Pellati, prepared for the Geological Congress, entitled Etudes sur les forma- 
tions ophiolitiques de U Italie,’ in which are set forth, with great conciseness, the principal 
facts with regard to the geography and the geology of these ophiolitic masses, and the 
theoretical views entertained with regard to them by various Italian geologists. Accord- 
ing to De Stefani, whose discussion is confined to the ophiolites of the Apennines, these 
rocks belong to three distinct horizons:—1. upper eocene; 2. upper trias ; 3. paleozoic ; 
none of them pertaining to a more ancient period. These ophiolitic rocks form zones and 
regular beds in the midst of the sedimentary rocks, and in no case plutonic dykes. The 
different varieties of serpentine, and of the non-sedimentary rocks which accompany, it, are 
themselves found in regular alternating bands. * The conception of this observer as to 
the mode of eruption of these rocks appears to be essentially the same as that of Issel, Mat- 
tirolo and Capacci, to be explained further on. (§ 91-93 and 100.) 
§ 46. The more recent studies of the R. Comitato Geologico, as announced in 1881, lead 
them to reject the views of De Stefani as to the age of the ophiolites, and to refer the 
whole of these rocks in Italy to two geological periods. They distinguish ancient serpen- 
tines, probably pre-paleozoic, and younger serpentines, referred to the tertiary. The older 
serpentines appear in large masses to the west of Genoa, between the valleys of the Polce- 
vera and the Teiro, and from thence are traced to Monviso, from which point the ophio- 
litic group passes north-northeast to Monte Rosa, and thence, by the canton of Ticino, to the 
Valtelline. To the same ancient series are also referred the serpentines of the north of 
Corsica, those of Elba in part, and those of northern Calabria. These ancient serpentines, 
according to Pellati, follow the contour of the great zone of old gneissic and granitic rocks, 
which passes along the Alps, through Corsica and the Tuscan archipelago, and re-appears 
in Calabria. The older geologists, Collegno, Pareto and Sismondi, regarded the serpentines 
of the areas thus defined (in common with the others yet to be mentioned), as haying been 
erupted, like granites, porphyries and basalts, at various geological ages. (Castaldi, how- 
ever, as early as 1871, assigned the Alpine serpentines to a distinct pre-paleozoic horizon, 
which, from the association of the serpentines with various rocks known as greenstones 
or pietre verdi, he designated as the pietri-verde zone, and compared with the Huronian of 
North America, of which he supposed it to occupy the herizon. 
§ 47. The conclusions of Gastaldi as to the Alpine serpentines have, according to 
Pellati, been confirmed by Baretti, and by Taramelli, the latter of whom clearly shows that 
the view held by many that the rocks of the pietre verdi are carboniferous or triassic, is 
inadmissable, and that they belong, as maintained by Gastaldi, to pre-paleozoic or eozoic 
time. All of the ophiolitic masses west of the meridian of Genoa, as well as those of 
northern Calabria, are, by Pellati, included in this class. 

* Boll. Soc, Geologica Italiana, i., pp. 20-53, 
