124 J.W.SPENCER — RECONSTRUCTION OF ANTILLEAN CONTINENT. 



then been active (Gabb), as well as several volcanic cones in the Wind- 

 ward group. 



The surveys of the sea of Honduras are much less complete than those 

 of the gulf of Mexico, but they are sufficient to indicate that a great por- 

 tion of that sea was shrunken to narrow limits, if not entirely drained. 

 Still, of this we have no proof at present, as the regular continuity of the 

 tributary fjords to the greatest depths is not shown by the incomplete 

 soundings so far made. In the oscillations of recent geologic times the 

 deeper portion of the Honduras basin may have remained a sea and 

 formed a retreat for such antique types of life as may be found in the 

 deeper Antillean waters. 



Drowning of the Pliocene Lands and Burial beneath marine 



Accumulations. 



In Cuba, Jamaica and San Domingo, resting upon the upturned edges 

 and denuded surfaces of Miocene and earlier formations, there is a de- 

 posit of soft, earthy, white or creamy limestone, made out of the mechan- 

 ical residue of older limestones, with some small masses of corals and 

 shells. All the observed species in Cuba* are the same as the living 

 ones.f To this formation the writer has given the name of the Matanzas 

 series. Owing to the modern facies of the organic remains, Salterain X 

 has included it in the post- Pliocene, but states that it may be Pliocene. 

 The accumulation occurs somewhat bedded, and has a thickness of about 

 150 feet. The beds generally lie at low angles, dipping (2° to 8°) toward 

 the coast or are nearly horizontal. This chalky limestone is soft and can 

 easily be cut, but soon hardens on exposure. It can be used for build- 

 ing purposes or as road metal. The lower bed, in which there are some 

 limestone pebbles from the older formations, has been seen to rise to 

 nearly 400 feet in altitude. It sometimes forms the barriers in front of 

 the modern bays, and these are then apt to be incised by recently formed 

 canyons, of which the outlet of the harbor of Cienfuegos is an example. 



In geomorphic position the Matanzas formation corresponds with the 

 Lafayette of Mr W J McGee, and also with some marine deposits of south- 

 ern Florida. Professor A. Heilprin has also found the same formation on 

 the northern plains of Yucatan. § From all the evidence before the 

 writer, he has placed the deposition of the formation at the close of the 

 Pliocene period, though in fact it may extend somewhat later. During the 



* "Geographical Evolution of Cuba," by the writer, in preparation. 



+ Dr W. H. Dall and Mr Charles T. Simpson kindly determined the fossils for me. 



J"Apuntes para una Descripeion Fisieo-Geologica de las Jurisdieciones de Habana," Madrid? 

 1880, p. 20. 



g" Geological Researches in Yucatan," by A. Heilprin, Proc. Acad. Nat. Sci. Phila. for 1891, pp. 

 136-158. 



