OVERLAND TO LA ESPERANZA 33 



tions, always going on within the sierras, break 

 down the mountains, ultimately entirely destroying 

 them. The walls on both sides of this pass are 

 concave and exhibit remnants of huge stalactites. 

 It is obvious that at one time the sierra at this 

 point was unbroken and continuous, but that a 

 cave formed gradually enlarging, until the weight 

 of the roof carried it down in a great crash. Some 

 of the remnants of this roof still exist in the form of 

 great boulders lying within the pass through which 

 the macadam road is built. This cave formation 

 explains many of the curious topographical 

 features of Cuba and Jamaica — the round deep 

 valleys (hoyos) of the former, and the "cockpits" 

 of the latter. 



Cuba is the richest island in the world for land 

 mollusks. It possesses more genera and species of 

 greater diversity and loveliness of form and color 

 than can be found in any other island, or equal 

 continental area in the world. The total is com- 

 posed of three faunulas, or elements, — correspond- 

 ing with the three mountain systems of the island. 

 While this can be recognized as "Cuban" in the 

 broader sense, it is nevertheless quite true that 

 these three subfaunas differ so markedly there is 



