276 BULLETIN OF THE 



These elevations may be only the remnauts of an aboriginal uneven 

 surface, but collectively they generally represent a higher land than 

 existed before the Cuchilla plains were developed. Whether the high 

 summits of the Sierra Maestra adjacent to the Santiago coast contain or 

 preserve traces of still older levels is an interesting problem for the future. 



These phouomena may now be grouped into three distinct age cate- 

 gories, one of which is still further divisible into many subdivisions. 

 These are (1) the modern or well preserved tripartite group of lower 

 lying levels, cliffs, or terraces, including the modern soboruco, tlie highest 

 level of which approximates three hundred feet ; (2) the dissected and 

 greatly denuded remnants of the old Cuchilla level, five hundred to seven 

 hundred feet above the sea, the remnant of an old general height whose 

 integrity is almost destroj'ed, and which is less easily traceable than the 

 first ; (3) remnants of the almost destroyed more ancient upland, as 

 preserved in the isolated buttes of the Yunque and Pan de Matanzas 

 type and the higher limestones of Santiago and Cienfuegos, which 

 demonstrate that there was once an old surface at least two thousand 

 feet above the modern sea level. 



The obvious history of these levels is as follows : — 



(1) In a period near the close of the Tertiary, to be ascertained, long 

 previous to the emergence of the present elevated reef and cautera and 

 the erosion of the Cuchilla plain, there was a great upward movement 

 of the island to the height of at least two thousand feet, which as yet 

 has revealed no history of its details further than that, from the absence 

 of later deposits and from the character of its ancient and much sculp- 

 tured topography, we may fairly infer that it has not since subsided 

 beneath the sea, but has remained mostly dry laud, and that its area 

 and outline were very neai-ly as great as those of the island of to-day. 

 This includes those portions of the island above the dissected Cuchilla 

 plain. 



(2) The Cuchillas at five-hundred-foot level constitute a plain or 

 plains produced by base levelling in the epoch immediately following 

 this oldest period of elevation, and represent the time interval between 

 it and the later movement recorded in the first or lower group. The 

 country was planed down by erosion to near sea level. The Cuchillas 

 summits indicate a long pausation period between the old Yunque and the 

 renewed modern elevation recorded in the Yumuri cliffs cut around them. 



(3) The tripartite group of modern cliffs and base levels below and 

 against the Cuchilla escarpment are the product of a renewed and mod- 

 ern upward movement, which elevated the old Cuchilla coastal plain to 



