256 BULLETIX OF THE 



forms the border of the mainland, but constitutes many bordering islets 

 of great areal extent. Generally these are low, standing only a few feet 

 above the water. There is a vast elongated archipelago of these elevated 

 reefs bordering the coast all the way from a point east of ]\Iatanzas to 

 Nuevitas. I passed most of this region in the night, and I can say 

 little concerning it. At Xuevitas, in the harbor, there are three peculiar 

 islands, known as Los Ballantos, which have very great resemblance to 

 the Keys of the Bahamas, presenting a bold, rounded escarpment at the 

 north point, composed of yellow friable material that may have been 

 pither coral sand or the yellow Miocene clays. It was impossible to get 

 ashore to these to examine them, although this was the only locality 

 seen by me where there wae a suspicion of wind-blown formation. The 

 greatest areal development of the Hat soboruco was found along the 

 outlet of this liarbor. 



Nowhere have I seen the elevated reef rock folded or otherwise dis- 

 turbed except by the gently coastward inclined elevation it has under- 

 gone. The interior margin I have never observed at a height of over 

 forty or fifty feet. In general, there is only one massive layer of this 

 old reef rock exposed, but at Matanzas there is undoubted evidence of 

 two older underlying reefs, the inner edges of which have been elevated 

 with the modern reef so that they do not form distinct terraces. It may 

 be that the apparently continuous reef around Cuba represents more 

 than one of these layers. Whether one or several alternations of reefs, 

 the soboruco as a whole certainly represents a recent and uniform ele- 

 vation of the whole periphery of the island at a verj- recent period of 

 geologic time, but sufficiently long ago to have permitted considerable 

 alteration and erosion. It is found from Cape San Antonio to Cape 

 Maysi on the north side of the island, and at many places on the south 

 side, e.specially near Santiago, as described by Kimball.^ 



Cantera is a term used tliroughout Spanish countries for any stone 

 that is soft enough to be hewn or sawed with ordinary carpenter's tools, 

 as distinguished from a stone requiring mason's implements. Much of 

 the cantera in Cuba is composed of a soft molluscan or coralline lime- 

 stone, which has not the irregularity of composition and density and the 

 varying hardness of the older limestone, nor the unaltered coral structure 

 of the elevated coast reef. It is intermediate between the two, and may 

 represent a stage in alteration between them. It is finely cellular, or 

 porous, not usually saccharoidal, and is filled with small cavities some- 

 times lined with botrvoidal lime coating. 



^ American Journal of Science, December, 1884. 



