82 Scientific Intelligence. 



The Miocene beds occur in the Rigi, the Pelerin and the Speer, 

 but are not known to occur in the synclinal valleys of the Alps; 

 they may yet be traced into some of them, but it appears certain 

 that the Alps had become mainly emerged by the commencement 

 of this era. 



The Flysch, the last of the Eocene marine deposits, is much 

 folded up with the beds below, entering into the remarkable dou- 

 ble folds; and it is probable that the great flexures of the Swiss 

 Alpine chain had hardly commenced before the era of its deposi- 

 tion had closed. The era of folding may have covered the whole 

 of the Miocene period". 



By the beginning of the Pliocene period, the folding was com- 

 pleted, and the Alps had acquired their present altitude or may 

 have exceeded it. 



The Glacial era probably began with the close of the Pliocene. 

 Then followed an interglacial period, represented by immense 

 accumulations of rounded, stratified gravel, which are situated 

 between two systems of angular erratics ; and during this epoch 

 the plains of Switzerland became free of the glacier. Later, 

 owing to new elevations or new meteorological conditions, the 

 ice spread itself anew over the plains; but whether to a greater 

 or less extent than in the first glacial epoch is uncertain. Then 

 followed the era of the formation of the great accumulations of 

 gravel in the Alpine valleys, and the terraced materials along the 

 lake valleys, and river borders, and the final retreat of the ice to 

 its present limits. 



3. Gradual variation in intensity of metamorphism. — A paper 

 on Crystalline and Metamorphic rocks of the lower Himalaya, 

 Garhwal and Kumaum, by C. S. Middlemiss, B.A. (Records 

 Geol. Surv. India, xx, part 3), gives some facts on this subject 

 which show that the metamorphic phenomena of India are much 

 like those of New England. The author emphasizes two points; 

 that " the schist near the gneissose granite is entirely a thorough 

 crystalline schist, a fact needing no miscroscope to demonstrate ; 

 and, secondly, along a line of countiy where rock is exposed at 

 every step, it is seen that this culminating intense form graduates 

 into a widespread less intense form, and this in turn, graduates into 

 ordinary slates and quartzites. " " About a mile from any outcrop 

 of gneissose granite, as we approach the Dudatoli massif, in no 

 matter what direction, there is a rapid, but gradual change in the 

 metamorphism of the schistose beds. The faint films of micaceous 

 material assume by degrees the aspect of distinct layers of mica- 

 plates of considerable thickness." "Garnets gradually assemble 

 in the schist; first showing as minute pin-heads under a coating 

 of what one may call mica-leaf, and gradually increasing in size 

 and definiteness concomitantly with the mica until they reach an 

 average size of peas and rarely as large as filberts. " 



An exact counterpart as to the change in the mica and garnets 

 with increasing intensity of metamorphism, connected with a 

 graduation from hydromica schist into gneiss occurs within 10 miles 



