194 DR. THOMAS STERRY HUNT ON THE 
the observations of Taramelli in the Valtelline, where he describes the ophiolites as lying 
below a great gneissic and granitic series, from which they are separated by a garnetiferous 
hornblendic rock and saccharoidal limestones. The lowest division in the series, as 
observed in the Valtelline is, according to Taramelli, a quartzose talc-schist, upon which 
reposes the serpentine in heavy continuous beds, having all the appearance of a stratified 
rock, followed by potstone, that is to say steatite or chlorite. To this succeed in ascend- - 
ing order, hornblendic and epidotic rocks, associated with crystalline limestones, often talci- 
ferous ; then, schistose amphibolite, talcose gneiss, tale-schists and eclogite, and finally a 
coarsely crystalline glandular gneiss, itself overlaid by granitic and associated hornblen- 
dic rocks. This apparent reversal of the succession as defined by Gastaldi and others, 
suggests the probability that we may have in the Valtelline an overturn of the strata, such 
as is well-known in many parts of the Alps, and elsewhere, placing the more ancient rocks 
above the younger ones. * 
§ 79. It is here the place to notice the mode of occurrence of the serpentines which, in 
Saxony, are found interstratified in the granulite series of the Mittelgebirge. The granulite 
proper may be described as a fine-grained gray laminated binary gneiss, consisting essen- 
tially or orthoclase and quartz, but often containing garnet and sometimes cyanite and 
andalusite. By an admixture of mica, it passes, through ordinary gneiss, into micas 
schists, which are abundant in the series. In it are also interstratified diclroite-gneiss, 
sometimes in great beds, and a greenish hornblendic gneiss, as well as the so-called gab- 
bros of the region (like that of Neurode.) These occur in larger or smaller lenticular inter- 
stratified masses, to which the distribution of the diallage in a granular labradorite base 
given a well-defined gneissoid structure. In this same series the serpentine is found in 
interstratified beds, occasionally garnetiferous, and sometimes associated with lherzolite. 
§ 80. I have not seen these rocks on the ground, but have examined a large collection 
of them in Leipzig, with the assistance of my friend, Dr. Hermann Credner, and was struck 
with their close resemblances to the rocks with which I am familiar in the newer or Mon- 
talban series of gneisses and mica-schists throughout the Atlantic belt of North America. 
The muscovite-gneisses of the Erzgebirge, with their occasional layers of limestone and 
of hornblende-rock, and their intercalated and overlying mica-schists, I also refer to the 
same general horizon. It is in these, it will be remembered, that are found the abundant 
conglomerate beds described by Sauer, the pebbles in which consist chiefly of varieties of 
granitoid gneiss, resembling closely those of the ancient gneiss of the Alps (Biellese) and 
the Laurentian gneiss of North America. These are, however, as I have seen, accompanied 
by pebbles of crystalline limestone. + 
Mention should also be made in this connection, of the existence of similar con- 
glomerates in Sweden, at Noljéarne, where pebbles of ancient gneiss and granite are found — 
at several points imbedded in fine-grained schistose gneiss, in calcareous mica-schist, 
and also in a red halleflinta, the strata of all of which are shown to rest unconformably 
upon the older granitoid gneiss. £ 

* Boll. Soc. Geologica Italiana, I., p. 14. 
+ Zeitschrift f. d. ges. Naturwiss. Band lii.; also Geol. Mag. Jan. 1882, and Bull. Soc. Géol. de Fr., x. 26; also 
Amer. Jour. Science, (8) xxvi., p. 197. - 
t Hummel, Om Sveriges Lagrade Urberg., ete., Stockholm, 1875, p. 30. 

