256 BULLETIN 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 Matanzas to 
Nuevitas. I passed most of this region in the night, and I can say 
little concerning it. At Nuevitas, 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 
either 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 was a suspicion of wind-blown formation. The 
greatest areal development of the flat soboruco was found along the 
outlet of this harbor. 
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 very 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, especially near Santiago, as described by Kimball.? 
Cantera is a term used throughout 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 botryoidal lime coating. 
1 American Journal of Science, December, 1884. 
4 
q 
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