RELATION TO MESOZOIC ROCKS IN THE LEPONTINE ALPS. 239 



supposition. If Jurassic here, they are also Jurassic in the Pennine 

 Alps, and would carry with them the " griiuer-s chief er " of Studer. 

 He commented on the brecciated character of the Rauchwacke. He 

 scarcely agreed with the Author as to the Jurassic schists resembling 

 poor forgeries of genuine garnet-schists, since it might be easy to 

 mistake some bands for parts of the calc-mica schists. 



Mr. Teall referred to remarks of his own on a previous occasion 

 as possibly having had something to do with the production of the 

 paper. We now had a further illustration that Prof. Bonney's views 

 were at variance with those of the modern school of Swiss geologists. 

 He had dealt with the age of the Yal-Piora schists on stratigraphical 

 evidence ; but we must wait to hear what the Swiss geologists had 

 to say to the criticisms of the Author. 



Speaking of the petrographical relations of the two rocks, he 

 agreed with Prof. Bonney that his specimens of the garnet- schists 

 were quite different from those of the Belemnite-rock. With refer- 

 ence to the character of the Belemnite-bearing rock, the Belemnites 

 themselves are marmorized; the rock itself is schistose, the planes 

 glistening with secondary (developed) mica ; the knots represented 

 some silicate. The prisms gave distinct outlines. There had been 

 much molecular change. In fact, he would term the rock a crystal- 

 line schist. 



Dr. Ieving, from personal experiences of traverses in the Eastern 

 Alps, could bear out the Author's views as to the succession of the 

 calc-mica schists &c. in the Glockner region and the small degree of 

 alteration of the rauchwacke in comparison with some of the dolo- 

 mitic series of the Eastern Alps. He had studied Grubenmann's 

 section of the Val Canaria, and criticized some of his deductions. 

 He regarded his assumptions as untenable — such as that the schists 

 are of Mesozoic age, chemically and morphologically altered by 

 pressure, or that the " calc-glimmer-schiefer " are altered limestones. 

 There was a third fallacy, viz. that of the two mica-schist series 

 recurring three times in the Val-Canaria section, yet only once in 

 such a position that their suggested origin would seem possible. 

 Lastly, Dr. Grubenmann had overlooked the important evidence of 

 the breccias in the dolomites. 



Prof. Hughes had been over the ground where the fossil-bearing 

 altered rocks occur, in company with Prof. Heim. He thought the 

 case one of evolution as far as the rocks are concerned. There was 

 a tendency to approach extinction-point, and when at last the fossils 

 disappeared alteration had gone so far that something altogether 

 different was produced. But there were degrees of alteration, and 

 many changes of known series, before we got to the Archaean. 



liev. E. Hill referred to the unlikeness of the Rauchwacke to the 

 older schists. 



The Author said that many of the objections proceeded from mis- 

 understanding. Heim's work dealt chiefly with the Central Alps, 

 of which he had not spoken, but he gave a complete contradiction to 

 any statements that these fossil-bearing rocks in the Lepontine Alps 

 are in any proper sense crystalline schists. There arc, however, 



