* 



Geological Notices of Barbary. 275 



left Algiers the 17th November, traversing the tertiary hills be- 

 fore mentioned, on its way to the plain of Metidjah,* and direct- 

 ing its route towards the south-west, on the road to Bleidah. The 

 plain was covered throughout with diluvial soil, lying in undis- 

 turbed horizontal layers, about 13^ feet thick, but in the bed 

 of the Chieffa, at the foot of the Atlas, it vvas about 33 feet thick. 

 The Metidjah is almost uninhabited, and nearly uncultivated, 

 except where it joins the Atlas; there the town of Bleidah is 

 charmingly situated, and almost surrounded with magnificent gar- 

 dens of orange trees. The chain of the little Atlas is here at its 

 greatest elevation, rising to more than 1200 metres, (3937 feet ;) 

 the valleys are deep and narrow, and the mountains covered with 

 woods. These mountains are formed of the same rocks as those 

 of Banjareah, near Algiers, with the strata dipping to the south : 

 they present the same aspect as far west as the great farm of 

 Huche de I'Aga; here the aspect of the mountains changes, they 

 lower rapidly to the wxst, the planes have a less inclination, the 

 vegetation is not as fine, and a change in the soil is announced. 

 The first rock that occurred on the Atlas was a greyish black 

 limestone, of a conehoidal fracture, passing into a marly and 

 schistose limestone, and alternately with schistose marls, in the 

 manner of the lias. The general inclination of the beds is to the 

 south, at an angle varying from 10 to 40°, for the hills and ta- 

 bles, and which in the great escarpements rose to 70°. The stra- 

 tification is often disturbed, but no volcanic rocks. This forma- 

 tion is poor in fossils, some broken pectens and ostrea, but no 

 gryphea, ammonites, or belemnites. The schistose marls contain 

 small bivalves, (possidonia) which in Europe are characteristic 

 of the lias. An hour before arriving at the Col de Temiah,+ 

 which is on the dividing water line, the mass is almost altogether 

 marly, the limestone becoming subordinate. The Col de Temiah 

 has been hollowed out of these marls; the general dip is to the 

 south. The strata south of the Col are cut by veins, almost ver- 

 tical, of carbonated iron, and laminar sulphated barytes, mixed 

 Vinth grey copper, malachite, and a little blue carbonate. These 

 veins are exposed about eighty metres, (262 feet) and the copper 

 might be worked to advantage. Calcareous and schistose marls, 

 and the laminar barytes, occur in like manner in Provence, Bur- 

 gundy, and Ardennes, and M. Rozet considers them true equiva- 

 • PI. 7. Fig. 2. f PI. 7. Fig. 2, continued. 



