of the Island ofCerigo and its Dependencies. 271 



mines worked in ancient times, such as those of silver on Mount 

 l^aurion, which Zenophon says yielded an annual income of 100 

 talents to the State ; we are therefore entitled to infer, that some 

 deposite of valuable ore may one day be discovered in Cerigo. 

 If there was a market, various quarries might be opened in the 

 clay-slate, limestone, and greywacke-slate, not only from being 

 easily worked, but also from their accessible nature and vicinity 

 to the shore. 



Stratification. — The direction of the limestone strata is N.E. 

 — S.W., dipping to the N.W. at an.angle varying between 15° 

 and 30°. Contortions of the strata are uncommon. 



Secondary Rocks appear to be entirely wanting in Cerigo and 

 its dependencies. 



Tertiary Rocks. — Several deposites met with in this island 

 are referable to the tertiary class. The oldest is a blue mar- 

 ly clay, containing numerous fossil marine shells; the genera 

 most frequently met with were ostrea, natica, buccinum, ebur- 

 na, turritella, cerithium, pleurotoma, and murex : it varies in 

 thickness from a few feet to many yards. In a transverse val- 

 ley a short distance to the north of the town of Cerigo, and 

 through which the principal or Potamo road runs, we have a 

 good example of it ; there at the upper part it alternates with 

 the lower parts of the next: deposite, which is a sand or sand- 

 stone ; again, in the escarpment of the valley of Tholaris, this 

 clay contains beds of brown coal. Resting then on the clay is a 

 calcareous sand or sandstone, of a brown or yellow colour, in 

 which were imbedded marine shells, although neither so abundant 

 nor of the same character as in the former ; the shells belonged 

 chiefly to the genera solarium, tellina, and ostrea. The next rock 

 in succession is a limestone which passes into a sandstone in its 

 lower parts, and into a marl in its upper, the central part is more 

 or less compact and generally inchnes to a yellowish colour, while 

 the upper is of a white or grey colour : it varies like the clay in 

 thickness from 50 to 200 feet, abounding in marine remains ; 

 the lower beds seemed to be characterised by the number of os- 

 treae and fossil corals they contained, while the upper may be said 

 to be characterized by their terebratulae, and the middle by their 

 abounding in large pectunculi and pectenes. Besides these^ many 



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