II.—On the Sand-grains in Micaceous Gneiss from the St. Gothard Tunnel; and on some other Difficulties raised By Prof. Bonney

• Published in: Geological Magazine
• Main Author: Stapff, F. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1894
• Subjects: Geology; Bonney; Anna Glacier
• Online Access: http://dx.doi.org/10.1017/s0016756800140774; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800140774

From the “Annals of British Geology,” 1892, No. 533, p.294, I find that Prof. T. Bonney doubts the occurrence of sandgrains in the Guspis micaceous gneiss, as stated by me in various reports on the geology of the St. Gothard Tunnel, and repeated on p. 17 of my “Remarks on Prof. Bonney's paper on the Crystalline Schists and their relation to the Mesozoic rocks in the Lepontine Alps.” The question being of some general interest, and not only of importance for the comprehension and classification of the crystalline schists in the Lepontine Alps, I think it desirable to repeat here the observed facts , and to present to the notice of the readers of the Geological Magazine some autotype prints of the rockinquestion. I am the only geologist who has seen these bedsinsitu, when they were opened by the St. Gothard Tunnel; and it would be rather difficult for anyone to make out their outcrops along the line of profile through the Guspis Valley and below the actual moraine of the St. Anna glacier, without taking into consideration the faults and thrusts in this tract, which are indicated on my geological map of the St. Gothard Railway and on the profile of the tunnel.