Notices and Extracts from the Minutes of the Geological Society. 171 



tainous groups are three or four spaces comparatively plain^ the most remark- 

 able beings that of Athens, which has a general direction from north-east to 

 south-west. This plain is bounded on the east, north-east, and north, by the 

 mountains Hymettus, Pentelicus, and Parnes ; and it is separated on the 

 north-west, from the plain of Eleusis, by a broken chain of hills, which is 

 continued from Parnes to the sea, and includes the ancient iEgialus and 

 Corydalus, between which is placed the convent of Daphne. 



The plain of Athens is subdivided by a series of hills, on part of which the 

 city is placed, including the connected group of the Museum, Pnyx, and 

 Lycabettus, — the Acropolis, Anchesmus (now St. George), and the ancient 

 Bulessus. Anchesmus may be estimated at about 1000 feet in height. 



The hills of the Pirseus, about 100 feet high, and Munychia, about 250 feet, 

 are detached from the remaining heights by a marshy tract, and bound the 

 plain of xVthens at the sea on its south-western extremity. 



The basis of all this country appears to consist of primary rocks, principally 

 of mica-slate, with granular limestone of several varieties : these constitute the 

 greater part of many of the mountains, and appear in the plains wherever the 

 rock is exposed. 



The greater part of Hymettus and Pentelicus is formed of granular lime- 

 stone. Chlorite slate occurs, in situ, close to Athens : and a compound of 

 felspar and diallage, with other rocks resembling serpentine, is found in de- 

 tached fragments in the bed of the Ilyssus, and on the west side of Hymettus. 

 Greywacke is observable at the base of the Museum. 



Above the primary rocks is a conglomerate, consisting of primary sub- 

 stances imbedded in a calcareous paste, which contains magnesia. The 

 conglomerate is visible, in its place, on the banks of the Ilyssus, at several 

 places on Hymettus, and at Daphne on the western verge of the plain of 

 Athens. 



A series of calcareous rocks, including a compact limestone of a splintery 

 fracture, and of various shades of grey and buff, forms the mass and superior 

 part of the range of hills which divides the plain of Athens. Among these 

 hills is found a breccia, composed of fragments of the calcareous substances 

 just now mentioned, united by a reddish calcareous paste, of a texture less 

 solid and uniform than the rock itself. The rocks of this series resemble very 

 closely the calcareous rocks of Gibraltar : and on the north side of Anchesmus 

 a loose spongy rock was observed, which appeared to have been deposited in a 

 fissure ; it contained fragments of the limestone, and in its texture, and brickr 

 red colour, was very similar to that which occurs in the crevices of the lime- 

 stone at Gibraltar. One of the specimens of this description contains a frag- 



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