ANNIVERSARY ADDRESS OF THE PRESIDENT. Mi 



of the Alps presented to the eye of every observer a confused heap of 

 ruin, before any general laws governing the lines of longitudinal frac- 

 ture, or the parallel foldings of the strata, were caught sight of, it 

 might be argued, that such chaotic disorder implied one or more 

 paroxysmal outbursts of subterranean force, wholly different from 

 ordinary volcanic or any other known agency. But Sir Roderick 

 Murchison agrees with an eminent foreign member of this Society, 

 Professor H. D. Rogers of the United States, and with several Swiss 

 geologists of distinction, that the dislocations and lateral movements 

 of Alpine strata have been obviously regulated by general movements, 

 in which system and law can be discovered. Mr. Rogers, you will 

 remember, declared in this room, when describing the structure of 

 the Alps and Jura, that he recognized a striking analogy between the 

 form of the flexures discernible in these European chains and those ob- 

 served by him and his brother in the Appalachians of North America. 

 In both cases the successive parallel folds have on one side a steep, 

 short dip, while the other side of the anticlinal flexure is longer and 

 less inclined. This longer side, in the Appalachians or AUeghanies, 

 dips towards the belt of intrusive volcanic rocks on the south-east 

 flank of the chain. So in the Alps, the steep, short dips do not face 

 the crystalline nucleus, but the longer and less inclined ones, except 

 where a curve has been so great that the whole are made to dip 

 one way, the more steeply inclined side having become as it were 

 more than vertical. 



In the Alps, the anticlinal folds, where they are greatest, dip in- 

 wardly towards the central peaks, and therefore in opposite direc- 

 tions on each flank of the chain. In the Jura, the steep, sharp dips 

 of each parallel fold are upon the side, facing the Alps, and hence 

 Professor Rogers imagines that the subterranean undulations in the 

 earth's crust, which, according to his theory, gave rise to these flex- 

 ures, were propagated, not from the Alps, but from the district of 

 the Vosges, or the country towards the north-west. To this theory 

 Professor A. Guyot strongly objects, arguing that it is more proba- 

 ble, on the contrary, that the immediate cause of the uplifting of the 

 Jura is to be sought in the upheaval of the Alps. " The elevation," 

 he remarks, " of the anticlinal ridges of the Jura diminishes gradually 

 and regularly in proportion as the Jura recedes from the Alps, the 

 summits sinking from 5000 to 2000 feet. The minor chains also of 



