180 Reports and Proceedings — 



a little actinolite and granules of haematite (?), and the clear mineral, 

 in some cases, seems to be quartz. The structure and most of the 

 minerals appear to be secondary. Chemical analysis shows the rock 

 to have been an andesite. A specimen from a third dyke is generally 

 similar, but is rather less distinctly foliated. 



A somewhat similar, but rather larger intrusive, mass by the side 

 of the Lago Bianco shows more actinolite and signs of primary 

 felspar, with other minerals. Here the rock retains some likeness 

 to a diabase. The resemblance of certain of these rocks to some- 

 what altered sediments is remarkable. The author considers the 

 bearing of this evidence upon other and larger masses of " green 

 schist " which occur in the Alps, and expresses the opinion that 

 their present mineral structure may be the result of great pressure 

 acting on more or less basic igneous rocks. 



2. " The Waldensian Gneisses and their Place in the Cottian 

 Sequence." By J. Walter Gregory, D.Sc, F.G.S. 



The lower part of the sequence of the Cottian Alps has been 

 universally divided into three series, of which the lowest has been 

 regarded as a fundamental (basal) Laurentian gneiss. It is the 

 object of the present paper to show that this rock is really intrusive 

 in character and Upper Tertiary in age. The writer endeavours to 

 show this by the following line of argument: — (1) The gneiss con- 

 sists of only isolated outcrops instead of a continuous band, and these 

 occur at different positions and not always at the base of the schist 

 series ; (2) the gneiss is intrusive, because : (a) it includes fragments 

 of the overlying series instead oi vice versa, (h) it sends off dykes of 

 aplite into the surrounding schists, (c) it metamorphoses the rocks 

 with which it is in contact, and [d) the schists are contorted near 

 the junction ; (3) the gneisses ai'e further shown to be later than 

 the igneous rocks intrusive into the " pietre verdi" series, as these 

 never traverse the gneiss. 



No positive opinion as to the age of the overlying schists is 

 expressed in the paper, though it is pointed out that the recent dis- 

 covery of radiolarian muds in the series may necessitate their 

 iuclusion in the Upper Palseozoic. The freshness of the gneisses, 

 the fact that these have not been affected by the early Tertiary 

 earth-movements, and the absence of authentic specimens of the 

 gneiss in the Cretaceous, Eocene, and Miocene conglomerate, renders 

 their late Tertiary age highly probable. 



The nature of the contact-metamorphism and the origin of the 

 gneissic structure are discussed, and a classification offered of the 

 earth-movements in the Cottian Alps. 



II. — Annual General Meeting. — February 16th, 1894. — W. H. 

 Hudlestone, Esq., M.A., F.R.S., President, in the Chair. 



The Secretaries read the Reports of the Council and of the Library 

 and Museum Committee for the year 1893. In the former the 

 Council congratulated the Fellows on the prosperous condition of 

 the Society's finances, drawing at the same time attention to the 

 continued decrease in the number of Fellows. 



