190 DR. THOMAS STERRY HUNT ON THE 
I have not seen the gneiss of the Finsteraarhorn, but having examined the gneisses 
and mica-schists of the St. Gothard and the Ticino, can affirm that they have the litholo- 
gical characters of the Montalban series of North America and of the younger gneiss and 
mica-schists of Gastaldi and von Hauer, in which they were included by the Austro- 
Hungarian geological survey. ({ 60.) The serpentines of the younger gneiss, as seen in the 
St. Gothard section, will be described in part. VII. 
§ 68. With regard to the presence of granites in these regions, Cordier, as cited by Lory, 
long ago asserted that true granites, occurring in veins or transversal inclusions, are rare 
in the Western Alps. He, however, excepted some masses, of which the granites of Baveno 
may be taken as a type, and others, which are rather veins of segregation (endogenous) 
than of injection. * For the rest, Cordier regarded the granites of the Alps as stratified rocks. 
Gastaldi, going still farther in his protest against plutonism, admits, in the regions exam- 
ined by him, none but stratified rocks of aqueous origin, and has included in his sections 
masses that I regard as igneous and intrusive rocks, but which are by him confounded 
with true indigenous gneissic rocks under the title of “ recent gneiss and granite.” 
As regards the porphyry mentioned in the sections of Neri as above the recent gneisses, 
and that placed by Gastaldi above the lustrous schists, it would appear that the latter em- 
ployed this term in a very vague sense, since he speaks of the feldspathic and quartziferous 
porphyries of this region as presenting great varieties in structure and in composition, and 
as passing into other rocks, notably into granites, from which it is often difficult to separate 
them. f He seems, under the general term of porphyry, to have included both stratified 
rocks at different horizons, and intruded masses of various kinds. 
§ 69. From the various descriptions and sections of the Alpine rocks, which we have 
here considered, it appears that they may be included in four distinct groups, which are as 
follows in ascefiding order :— 
I. The central or ancient granitoid gneiss, with occasional quartzites and crystalline 
limestones, bearing graphite and many crystalline minerals. This group we refer, with 
Gastaldi, to the Laurentian. 
II. The great group of the pietre verdi proper, in which, besides serpentines and ophio- 
litic rocks are included bands of limestone, and also apparently certain gneissoid rocks, the 
protogine or the talcose gneiss of Lory and Taramelli. (§ 61, 78.) It is worthy of remark that 
although Gastaldi, like Neri, Gerlach and Von Hauer, placed the great group of recent 
gneiss and mica-schists above the true pietre-verdi zone, which he declared to be com- 
fined between the older and the newer gneiss, he, in his last published sketch, indicated 
besides this, another horizon of “recent gneiss and granite” (not elsewhere noticed by him) 
intercalated in the pietre-verdi zone, as thus limited, and probably corresponding to these 
talcose gneisses. This second or pietre-verdi group, we refer with Gastaldi to the Huronian. 
III. The younger gneiss and mica-schist series, with hornblendic varieties and interca- 
lated crystalline limestones, and in some cases with serpentines and euphotides. This 
group. upon the lithological characters of which we have already insisted, (§ 53, 55, 67) we 
regard as the representative of the Montalban. 
IV. The upper lustrous schists with gypsums and karstenite and talc, with inter- 

* See the author in Chem. and Geol. Essays, page 331, 
+ Studi, ete., part IL, p. 34, 

