.^""o. 1.] MATTHEW — IMPRESSIONS OF CUBA. 25 



-and enters Xagua Bay just west of Cienfuegos. The fossiliferous 

 layers rest upon certain buif-colored clays which form the subsoil 

 at many points near the town, and which are covered here and 

 there to a depth of from three to four feet by quartz gravel and 

 sand. The coarser deposits have the aspect of ancient beaches or 

 Tidges, formed at the time when the depression in which they lie 

 was a shallow cove extending behind the site of the town. 



The shells in these sand and gravel beds are all of littoral 

 species, and the water in which they lived appears to have been 

 subjected to more or less agitation; for they are worn and the 

 valves of the lamellibranchiates are oenerally severed from each 

 other. The great majority of the species occurring here as fos- 

 sils are still living on the neighboring coast ; and from the rela- 

 tions of the deposit in which they are found, as well as the thin- 

 ness of the beds, their want of coherence, and slight elevation 

 above the Bay, I had supposed them to be Post-pliocene ; but 

 Mr. Guppy, to whom the shells collected here were referred, 

 regards them as " probably Pliocene.'' The following are among 



the species occurring here. 



Murex brevifrons, Bulla striata, 



Stromhus gigas^ Ostrxa, sp. 



S.pugilix, Perna obhqua, 



Pgrida melongeva, Mi/tlluR, Sj>. 



Xerita tessellata ? Venus cancellata, 



Keriiinia virginea, Lucina costata ? 



Modulus lenticularis, L. tigrina (young), 



Cerithium versicolor, L. Jamaicensis, 



C. vulgatum, A^aphis rugosa. 



At Santa Lucia Brook on the Damuji Biver there is a deposit 

 •of buff-colored, calcareous marl, which at some points nearly fills 

 the little valley through which this stream runs. I had no means 

 •of measuring its height above the river, which at this point is a 

 tidal estuary, but think that it may be roughly estimated at one 

 hundred feet. This calcareous mass contains leaves of the jucaro, 

 or olive-bark tree, Bite ida JSuceras, the two mangroves i^/u'zoj^Aora 

 mangle and Avicennia nitula, a fern, a palm ? and fragments of 

 other plants. With these there were a few valves of a large spe- 

 cies of oyster and some mussel shells, apparently the same spe- 

 cies as that occurring in the surface beds at Cienfuegos. 



Intermediate in height between the marl of Santa Lucia 

 brook and the deposits already described near the sea-level, there 

 as another surface layer of a dark color exposed along the slopes 



