564 Prof. Pantanelli—The Jaspers of Tuscany. 
TII.—1 Draspri pera Toscana £1 LoRO Fossiu1. Per Prof. Dantxr 
Panranetit. Mem. della Reale Accad. dei Lincei. Ser. 3, vol. 
vill. June, 1880. 
ROF. DANTE PANTANELLI has presented a valuable memoir 
P on the Jaspers of Tuscany, in which he has found, as mentioned 
in his preliminary announcement, a large number of Radiolaria.* 
Tn the definition now given of the rock, it is said to be constituted 
of amorphous silica, together with crystallized silica, stained with 
metallic and earthy oxides, often distinctly crystallized in the mass 
of the silica. It contains the remains of organisms with siliceous 
skeletons, and occurs in clefts and in raised and stratified masses. 
This “diaspro” is abundant in various horizons of the Upper 
Eocene of Tuscany, and is found in stratified layers which rarely 
exceed five centimétres between the hard masses of clay called 
galestro, and sometimes between incoherent material or strata of 
siliceo-calcareous rocks. 
Professor Pantanelli describes thirty-two species of Radiolaria 
from the ‘“diaspro,” and says they are larger than their living allies, 
and after a criticism of the results of the Challenger and other expe- 
ditions, concludes that these deposits have been formed in not less 
than one thousand metres, for the number of Radiolaria is known to 
increase with the depth, while the number of Foraminifera on the 
other hand diminishes. 
Geologists have maintained that the origin of diaspro was meta- 
morphic, or at least the result of silicification posterior to deposition, 
until De Stefani a few years ago doubted the correctness of this idea, 
and it is now shown that the rock in question cannot be formed by 
metamorphism caused by the vicinity of igneous rocks for several 
reasons ; among others, it could not attain such great thickness, nor . 
as now shown contain fossils; nor is it only found in the Hocene, 
where metamorphic action might be attributed to the serpentine, 
but also in the Chalk and Lias, where no eruptive rocks are known ; 
and further, in the Hocene the “ diaspro”’ is often very far from any 
igneous rocks. Calcareous or sandy strata are sometimes intercalated 
in the galestro, and in the same way the serpentines are sometimes 
separated from the galestro by unaltered calcareous strata. 
Professor Pantanelli considers that this compact rock is formed in 
much the same way as calcareous ones by analogous phenomena, the 
incoherent material in this case being agglutinated by the silica in 
solution in the acid water, so that the cracks, instead of being filled 
with calcite, as in the latter case, are full of quartz. 
Stoppani, De Stefani, Bonney, Issel, have recently maintained that 
the serpentines represented true submarine lavas of the Upper Eocene, 
and this receives additional support, or rather proof, from the present 
discovery, and at the same time the presence of these fossils excludes 
the idea of the galestro and other of the series having a metamorphic 
origin. A. W. W. 
* See preliminary notice, Gzon. Mac. 1880, July No. p. 317. 
