152 SCIENCE PROGRESS. 



which consist of materials from the north slope of the zone 

 of Mont Blanc. Toward the end of the Flysch a great 

 part of the Alps, including the Prealpes, was elevated 

 and glaciers formed upon the highest peaks. These 

 brought into the basin of Lake Thun masses of the granite 

 of Baveno and Predazzo, of the porphyrites of Lugano, and 

 of the protogines of Mont Blanc and the St. Gothard. 

 This would have been quite impossible if an arch had 

 connected the zones of the Prealpes and that of the 

 Brianconnais, and covered the area from which these rocks 

 have been derived. 



Professor Schardt's theory has been attacked from an- 

 other side in a short but extremely interesting paper by M. 

 E. Haug (4). In this he considers the origin of the Pre- 

 alpes, and offers another explanation of the resemblances 

 between the rocks of this zone and that of the "Zone du 

 Brianconnais ". Bertrand has laid it down as a geological 

 law that folds reproduce themselves along the same lines. 

 Therefore, if we want to find the site of the ancient lines 

 of earth movements in an area, we must look for them 

 below the lines along which great folding may be seen in 

 the rocks at the surface. 



Haug accepts this law, and his paper is devoted in the 

 main to applying it to the Prealpes. He shows that the 

 Carboniferous rocks are developed in two basins, an internal 

 one which passes from Liguria to Briangon, through the 

 Tarentaise and the Maurienne, to the Little St. Bernard 

 and aloncj the Rhone Yallev. To the west of this is a great 

 anticlinal line, which represents an old pre-Carboniferous 

 mountain range. Beyond this comes an external band 

 of Carboniferous rocks, which were deposited in another 

 synclinal. 



In the Permian we get the same arrangement repeated ' 

 two bands of Permian rocks deposited in synclinals and 

 separated by a great anticlinal. With the Trias this 

 arrangement is repeated again. 



In the next system, however, there is a change, for the 

 whole of the zone of the Brianconnais was then raised as 

 a great anticlinal. The summit was above the sea level, 



