794 THE JOURNAL OF GEOLOGY. 



ically it is chiefly characterized by the abundance of hornblende- 

 augite-andesite. The fifth and last district, made up of Mt. 

 Oros and its outliers, and to be known as the Oros District, occu- 

 pies the whole southern angle of the island. Orographically, the 

 subordination of the outlying members to a main central mass is 

 much more clearly marked here than in the other cases. The 

 main rock mass is an augite-hypersthene-andesite with later 

 eruptions of dacite. 



It may be mentioned here that neither on /Egina nor on 

 Methana did I meet with any dikes, sheets, or other such intru- 

 sive bodies : the bearing of which point on the eruptive character 

 of the region will be discussed later. 



The north and northwest shores are low and flat, rising very 

 gradually to the foot of the east and west running mountain 

 range. This shore land, which is of late Tertiary age, is composed 

 of horizontal [beds of marl and a soft cream-colored limestone, 

 such as is known throughout Greece as " Poros Stone" [-n-^pivo? 

 Attfos^ which is extensively used for building purposes, being 

 soft and'easily cut when first quarried, but hardening consid- 

 erably on exposure. Along the north coast these beds give 

 place to a breccia of limestone blocks cemented by a soft calcar- 

 eous cement, which occupies the foot of the mountain range just 

 mentioned. 



Thisjf range, which belongs to the second district, embraces 

 the mountains of Kokkalaki, Baro (199 m.), and the ridge (191 

 m.) on which stand the well-known ruins of the ancient Greek 

 temple of Athena. These mountains are carved out of nearly 

 horizontal beds of the gray or yellowish crystalline Cretaceous 

 limestone (containing rudistes) which forms such a prominent 

 geological feature of this part of the Balkan peninsula. The 

 southern side of Mts. Kokkalaki and Baro is quite steep, the 

 lower part being in places almost perpendicular — evidently 

 an old shore cliff, the lower part of which is now invisible. 

 On the south slope of Mt. Baro there crops out a horizontal 

 stratum of dark red shale, and a similar, though smaller outcrop 

 is seen near the west end of Mt. Kokkalaki. (Cf. Fiedler, I., 273.) 



