St. Jago. 



PART I. 



The island since being inhabited has not suffered from 

 destructive earthquakes. 



The lowest rocks exposed on the coast near Porto 

 Praya, are highly crystalline and compact ; they appear 

 to be of ancient, submarine, volcanic origin ; they are 

 unconformably covered by a thin, irregular, calcareous 

 deposit, abounding with shells of a late tertiary period ; 

 and this again is capped by a wide sheet of basaltic lava, 

 which has flowed in successive streams from the interior 



No. 1 



Signal 

 Post Hill. 



Ribeira 

 Grande. 



Porto Praya. 

 PART OF ST. JAGO, ONE OF THE CAPE DE VERDE ISLANDS 



of the island, between the square-topped hills marked 

 A, B, C, &c. Still more recent streams of lava have 

 been erupted from the scattered cones, such as Red and 

 Signal Post Hills. The upper strata of the square- 

 topped hills are intimately related in miner alogical 

 composition, and in other respects, with the lowest series 

 of the coast-rocks, with which they seem to be continuous. 

 Miner alogical description of the rocks of the lowest 

 series. — These rocks possess an extremely varying char- 

 acter ; they consist of black, brown and gray, compact, 



