of the Leponiine Aljjs. . 7 



1875, and I am glad to find it supported by so high an authority. 

 In a paper I read at the 58t|' annual meeting of the Schweizerische 

 Naturforschende Gesellschp o, held at Andermatt, September, 1875 

 (Jahresbericht, 1874-5, pp^ 127—156), is the following:— 



" Worthy of attention is the frequent association (in the southern 

 section of the Gothard tunnel, 700 — 800 m. from the mouth) of this 

 calc-mica schist with dark, dense, often phyllitic mica schists which 

 resemble some of the Nufenen ' Knotenschiefer ' in having knobs of 

 small garnets. But it should be kept in mind that two different 

 kinds of spotted schists occur in the Nufenen pass. In one of them 

 the knobs are garnets ; in the other one cylinders and hail-like 

 grains of a zeolithic ^ mineral, and the belemnites are exclusively 

 found in this last-named variety" {I.e. p. 140). Further, the fol- 

 lowing will be found in the text to " Profil geologique du St. Gothard 

 dans i'axe du grand tunnel etabli pendant la construction (1873- 

 1880) par F. M. Stapff, ingenieur-geologue de la Compagnie du St. 

 Gothard" (Annexe speciale aux rapports du Conseil federal Suisse 

 sur la marche de I'entreprise du St. Gothard; Berne, 1881), "The 

 blach scliists of the Oberalp road (north side of the Gothard) might be 

 paralleled with certain black garnet schists of the south side (Nufenen 

 schists in part.) — Footnote. The belemnites do not appear in 

 the black garnet schists of the Nufenen pass, but in a kind of 

 black schist which much more reminds one of those from Altkirche 

 (likewise on the north side of the Gothard, not far from the Oberalp 

 road). The cylinders in this rock are composed of a zeolitic 

 mineral (comp. von Fritsch, p. 127) which probably accounts for the 

 hydraulic qualities which calcined lime exhibits when mixed up with 

 slightly burnt and ground belemnite-schist from the Nufenen. If 

 this parallelization be correct, and the metamorphosed sedimentary 

 rocks of the Ursern valley properly determined, then we may draw 

 the conclusion that the series of the originally sedimentary rocks 

 on the south side of the Gothard begins, at the bottom of the Ticino 

 valley, with Jurassic deposits and includes Carboniferous at about 



^ I am well aware that these grains and cylinders in the Nufenen schists are 

 usually considered to be couseranite; but the existing chemical analyses allow them to 

 be equally as well regarded as i. i.prehnite, and this interpretation is not contradicted 

 by Prof. Bonney's microscopic analysis, though the shape of the prisms does not 

 agree with the usual habit and mode of occurrence of prehnite. 

 Comparative analyses : — 



le Nufenen 



To be compared with 



Prehnite 43-63 Couseranite 52-37 



24-87 24-02 



( 6-81 — 7 -38 in some varieties) — 



27-14 11-^5 



_ 1-40 



4-36 KaO.NaO 9-48 



100-00 100-16 100-00 99-12 



I observed the hydraulic character of the Nufenen schists whilst searching for 

 hydraulic lime in the neighbourhood of Airolo, and made some laboratory tests with 

 them. 



