274 Geological M)tices of Barbary. > 



at least as far as Cape Corinna. The fort of Twenty-four hours, 

 and all the buildings of the mole, stand upon the grey limestone. 

 About the mole the beds dip to the east. The gneiss forms a 

 somewhat narrow belt, stretching from east to west. It leaves the 

 sea-shore in front of fort Babazoum, passes to the emperor's castle, 

 and the mountains which command that fortress, and is lost to the 

 south under the tertiary deposits. M.Rozet remarks, that this gneiss 

 which has all the characters of a primitive rock, reposes upori talcose 

 schists, which appear to belong to the transilio?i; but that the veins of 

 mica schist passing through the gneiss, prove this last to be the old- 

 est rock, although it covers the talcose schists which pass into mica 

 slate. We leave the French geologists to reconcile this unconforma- 

 ble condition of gneiss to the modern opinions concerning transition. 

 The gneiss dips to the south, under the tertiary, a calcaire 

 grossier, (London clay), or a gres calcaire, (calcareous sandstone,) 

 passing into a pudding stone, resembling the calcaire moellon of 

 Montpelier. These calcareous beds, like the gneiss, on which they 

 repose, dip to the south. They pass occasionally into compact 

 limestone, (at Staoueli) containing limnea and helices, together 

 with marine shells. In other places, M. Rozet found large flat 

 oysters, and large pectens, resembling those which characterize 

 the beds in Provence. The tertiary abounds along the coast, 

 from the Swedish consulate to El Aratch, with well preserved 

 pectens, large oysters, and some terebratulce. The tertiary is 

 covered with diluvial soil, but in no part had fossil bones of quad- 

 rupeds been found. The tertiary formation is thought to cover 

 a surface of country of twenty square leagues. The table lands, 

 the plains, and the bottoms of the valleys, are covered with dilu- 

 vial soil, resembling that of France. The superficial part is 

 formed of a red or yellowish marl ; beneath it is a mass of marl and 

 rolled pebbles, all derived from the neighbouring mountains. On 

 the narrow plain to the east and west of Algiers, the diluvial soil 

 is more than ten metres (32 feet) thick, with some boulders. M. 

 Rozet finds a strong analogy between the geological phenomena 

 of the opposite coasts of the Mediterranean. 



Geological Notice of the country traversed by tlie French army, in 

 the expedition of Media. 

 To punish the Bey of Titery for his treason, General Clausel 

 resolved to seek him out in the middle of the Atlas. The army 



