480 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 30, 



May 30, 1860. 



Mark Fryar, Esq., Lecturer on Mining, &c., at the Andersonian 

 University, Glasgow, and Francis Duncan, Esq., Lieut. E.A., 

 Halifax, were elected Fellows. Dr. Henry Milne-Edwards, Professor 

 of Zoology &c, Jardin des Plantes, Paris, was elected a Foreign 

 Member. 



The following communications were read : — 



1. On certain Eocks of Miocene Age in Tuscany, including Ser- 

 pentine, Copper-ores, Lignite, and pure Alabaster, used in 

 Scidpture. By W. P. Jervis, Esq., F.Gr.S. 



[Abstract.] 



The geology of Tuscany is peculiarly interesting, though presenting 

 many difficulties to the palaeontologist and field-geologist, owing to 

 the diversified changes which have been produced on the sedimentary 

 strata since their consolidation. 



These metamorphic agencies are still at work .in Central and 

 Southern Italy, either in the form of simple hot vapour-emanations, 

 or the more extended and allied volcanos whence solid matter is also 

 ejected. On the other hand, no such phenomena are seen N. of the 

 Arno, where nature has been comparatively quiescent since the close 

 of the Miocene period. 



Most of the metamorphoses of the Italian rocks appear to be of 

 comparatively recent origin ; nor can I find any proof of their exist- 

 ence at all previous to the close of the Mesozoic period or the be- 

 ginning of the Eocene. Serpentinous rocks then first upheaved the 

 littoral of Piedmont and Tuscany, where they formed the eastern 

 barrier of the Maremme,— probably producing an archipelago of 

 little islands surrounded by an iron-bound coast, many of them 

 rising to the height of several hundred feet, covered by a peculiar 

 flora in certain portions where soil was formed by the disintegration 

 of the magnesian rocks. Four consecutive and allied eruptions are 

 distinguished by Italian geologists. Three are considered as having 

 occurred during Tertiary times; the fourth, during the Mesozoic 

 epoch, is the oldest, and must be first spoken of. 



The geography of the Serpentine-eruptions has been described by 

 Savi, who enumerates four series, lying more or less parallel to the 

 chain of the Apennines. Throughout the whole of Italy, the litho- 

 logical appearance of each successive eruption is so typical that it 

 may be easily borne in mind, arising from the fact that the elements 

 of which they are composed have a widely different chemical consti- 

 tution — probably due to the then molten matter having been ejected 

 from different depths, perhaps even from different foci. In order to 

 describe the Miocene eruptive rocks, we must first refer to the pre- 

 existing eruptions to which I have just alluded ; otherwise the phe- 

 nomena which present themselves will not be so well understood. 



I. Diallagic Serpentine. — Never enclosing fragments of Tertiary 



