276 



Geological Notices of Baibary, 



lents. This formation constitutes mountains 1100 metres (S609 

 feet) above the level of the sea, with few escarpments, although 

 a talus is generally to be observed. The timber is oak and cork. 

 There are no fruit trees in the Atlas, and the olive is only found as 

 far as Media. After passing the Col de Temiah, the road is ex- 

 tremely difficult, with scarce room for two to pass abreast ; and 

 after a march of an hour and a half, the army came to the foot 

 of the chain, upon a small narrow table land, perfectly smooth. 

 A new change in the beds appeared here, the hills were closed 

 in by the sub-appenine formation. At the foot of the chain, the 

 hills which abut upon the lias, are entirely composed of an ar- 

 gillaceous blueish marl, not schistose like that of the north ; about 

 100 metres thick, (328 feet) and no appearance of stratification. 

 It contains gypsum, which furnishes plaster for the buildings at Me- 

 dia, Pectens, Pectunculi ; and an immense quantity of that murex, 

 which is characteristic of the calcareous moellon of Provence, is 

 found in a yellow ferruginous sand stone, alternating with ferrugi- 

 nous sand, at the upper part of the hills. As far as Media, three 

 leagues south-east from the Atlas, and a league further to the 

 south, M. Rozet found the tertiary formation occurring in like 

 manner. The town of Media* occupies the summit of a hill, situa- 

 ted upon the north flank of a great valley, which runs nearly 

 ii'om east to west. Section No. 2, terminates at this valley, and 

 No. 3, made about three miles east of it, traverses the same val- 

 ley, and shows the details of the sub-atlantic tertiary. This for- 

 mation constitutes hills and small mountains, some of which are 

 1000 metres, or 3280 feet above the level of the sea, and is en- 

 tirely identical with that of those hills, which, stretching along 

 the coast from Cape Matifon to Cherchel, border the plain of Me- 

 tidjah to the north ; so that this tertiary has been deposited on 

 each slope of the little Atlas, but not in the interior of the chain. 

 M. Rozet concludes this interesting paper, by showing that the 

 beds of the lias being highly inclined, and the tertiary deposits 

 abutting horizontally against them, the chain of the little Atlas 

 was necessarily raised before the deposit of these last. 



In a subsequent paper, M. Rozet further shows that to the 

 north of Metidjah, the hills which extend from Cape Matifou to 

 beyond Rubber Romerh, are formed of sub-atlantic tertiary, of 

 the same character as that south of the little Atlas. Blue marl, 



• PI, 7. Fig. 3. 



