Ixviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



height of 3124 metres a little to the eastward of the Diablerets. A 

 short notice of this wUl not, I think, be uninteresting, as giving a 

 clear explanation of some of the complicated structures of the 

 secondary beds in this portion of the Alpine chain. After describing 

 the orographical limits of what he calls the massif of the Oldenhom, 

 which is separated by a fault from the Col de Pillon on the north 

 or north-west, he describes the different formations of which the 

 northern slope of the mountain consists. These are broken into 

 several alternating anticlinal and synclinal masses,or,as he calls them, 

 combes and vallons, or saddles and troughs as they are sometimes 

 called. It forms a portion of the Cretaceous and Nummulitic zone of 

 the Alps. The principal nucleus of the formation is JSTeocomian, par- 

 tially covered over by the Urgonian limestone, resting on which are 

 occasionally found fragments of the Nummulitic beds, these generally 

 occur in the troughs formed by the synclinal arrangement of the 

 Urgonian limestone. Without going into all the details given by 

 the author, it may suffice to say that these beds, which are sometimes 

 seen in an almost horizontal position, become, higher up the moun- 

 tain, completely vertical or even sometimes slightly inverted to- 

 wards the north. This alternation is repeated several times. 



This remarkable arrangement, he observes, is precisely similar 

 to the saddles and troughs of the Jurassic chain, with this difference, 

 that the system of contortion which in the Jura has a horizontal 

 base, must be referred in the Alps to a highly inclined base line, 

 so that the two sides of a trough which in the Jura " are symme- 

 trically inclined, become in the Alps the one horizontal, and the 

 other vertical." This is well shown in his section of the Sanetsch, 

 where he has drawn an inclined ideal base line, which, when placed 

 in a horizontal position, reduces the Alpine contortions and inversions 

 to simple Jurassic undulations ; by this means the structure of the 

 Alpine beds is wonderfully simplified, and throws an interesting light 

 on the mode of elevation of the chain of the Alps. Here, at least, it 

 appears that the elevation of the Alps presents two principal elements. 

 The first action formed the undulations of the beds, producing a 

 structure analogous to that of the Jura; by the second, the whole 

 mountain-mass underwent an unequal amount of elevation starting 

 from the centre of the chain, producing an inverse effect on the un- 

 dulating beds, raising up and overturning some, while others were 

 brought into a horizontal position. This semi-jurassic orography 

 has given him the key to other stratigraphical arrangements in the 

 Alps, even more complicated and unusual. 



The author then proceeds to describe the various formations, the 

 most recent of which is the Nummulitic, which consists of four dis- 

 tinct beds, and, as I have observed, always occurs in the troughs 

 formed by the synclinal Urgonian limestone. He mentions various 

 points where it is seen, and the different fossils by which it is cha- 

 racterized. Several species of CeritJiium are abundant in the lowest 

 bed. 



The next formation is the Urgonian. No traces of the Cenoma- 

 nian, Gault, Aptian, or Ehodanian have been here found. The Ur- 



