180 DR. THOMAS STERRY HUNT ON THE 
least, assigned to the cenozoic period, “they are practically identical” with the serpentines 
and gabbros of more ancient times. 
§ 42. Bonney further calls attention to the breccias of serpentine with a calcite cement, 
found at various points with these Italian serpentines, and concludes that the serpentines 
have been brecciated in situ, so that it is possible to trace, in a short distance, the passage 
from unbroken or slightly fissured blocks to completely crushed and recemented fragments, 
and even to mixtures of finely broken serpentine cemented by carbonate of lime, in which 
he notes, here and there, filmy patches of a serpentinous material, as if it had been redis- 
solved and again deposited. He believes that the crushing took place after the rock became 
a serpentine. The correctness of these views of Bonney as to the breccias, I can confirm 
from my own observations in the same regions, and also from my studies of similar brec- 
clas accompanying the ophiolites of eastern Canada. Gastaldi, in this connection, has made 
an important observation of a breccia in the valley of Trebbia, resting upon a diallagic ser- 
pentine, and consisting of cemented fragments of silicious and argillaceous slate with lime- 
stone (alberese), the paste being tiaversed in various directions by veins of chrysotile. * 
§ 43. Bonney’s observations thus bring us face to face with the views of those Italian 
geologists who regard certain of these serpentines as of tertiary age, and speak of them 
as having had an eruptive origin, although, as we shall see, their views of the genesis of 
these rocks differ as widely as possible from those of Prof. Bonney. In anticipation of the 
International Geological Congress at Bologna in September, 1881, the Italian geologists 
had, under the direction of the Royal Geological Commission (R. Comitato Geologico), 
made extraordinary preparations for the study the full discussion of the problems 
offered by the serpentines of Italy. A map, prepared for the occasion, was published, show- 
ing the localities of the ophiolitic masses for the whole kingdom ona scale of 1-1,111,111th ; 
besides separate maps of particular regions on a scale of 1-10,000th, as that’ of Mazzuoli 
and Issel forthe Riviera di Levante in Liguria, and that of Capacci for Monteferrato in Prato, 
in Tuscany ; with especial memoirs on these districts, also published by the R. Comitato 
Geologico in 1881. Ophiolitic rocks are met with in greater or smaller outcrops in many 
localities from the Alps, throughout the Apennines, and as far as Calabria. To these, the 
studies of Taramelli, Lovisato, De Giorgi and De Stefani, among others, in addition to 
those previously named, have contributed a great body of information. A collection of 
ophiolitic rocks from various localities was also made and submitted to chemical and 
microscopical study by Cossa of Turin, aided by Mattirolo, the results of which occupy 
about 200 pages, illustrated with many plates, in the fine quarto volume recently pub- 
lished on Italian lithology. + 
§ 44. During the International Geological Congress, a special meeting was held for the 
discussion of the question of serpentines, on September 30, 1881, in which took part, Tara- 
melli, Capacci, Zacagna, Sella, Szabo, Daubrée, De Chancourtois and the writer, who pre- 
sided on that occasion. A detailed report of the proceedings at this meeting is published 
in the first fasciculus of the Bulletin of the new Geological Society of Italy, pages 14-51, 
followed by an address on the general subject of serpentines by the present writer, pp. 32-58, 
by notes on the same subject by De Chancourtois, pp. 39-44, and finally by the extended 

* Studii geologici sulle Alpi occidentali, parte IT, p. 51. 
+ Ricerche Chimiche e Microscopiche sui Roccie e Minerali d'Italia, Torino, 1881. 
