MUSEUM OF COMPARATIVE ZOOLOGY. 273 



with the sea are subjects conceruing which I am at a loss to offer 

 explanation. 



The geologic section (Plate I. Fig. 4) of the caxion shows that there 

 are at least three alternations of old reefs and thin gravel beds, which in 

 turn rest upon a great thickness, not less than eight hundred feet, of 

 the older Tertiary limestones, out of which the amphitheatre proper is 

 carved. The beds are all tilted to an angle of fifteen degrees, but the 

 highest elevation of the undoubted coral laid down against the old 

 limestone is less than one hundred feet. 



That this amphitheatre was once an indented harbor and the Yumuri 

 River canon its outlet, is a hypothesis which may he suggested. The 

 denuded floor shows no trace of evidence that would convey this impres- 

 sion, but around the walls of the amphitheatre are traces of terraces 

 corresponding in height to the hundred-and-fifty-foot bench outside 

 the harbor, and these may represent the former floor of the amphi- 

 theatre when at sea level. If they do, then the Versailles, or highest 

 elevated reef rocks, were formed off the point of an old outlet through 

 the Yumuri. In the canon itself, however, there is no distinct evidence 

 of planation terraces, such as would indicate pausation periods followed 

 by renewed epochs of cutting, although just out of it on the west side of 

 the harbor, back of Versailles church, old river gravels are preserved 

 about twenty feet above sea level. 



Between Havana and Matanzas the interior is a very broken country. 

 The railway runs back of the interior of the escarpment of the old coast 

 limestones, and sub-parallel to them, for thirty-six kilometers from 

 Havana, upon a floor of underlying metamorphics, constituting a very 

 hilly country. At thirty-seven kilometers the railway again cuts the 

 bottom of the limestone at an altitude of two hundred feet, enterinjr a 

 level limestone plain at Aguacate, separated by a deep eroded valley 

 from a range of limestone hills two kilometei's to the north. At sixty- 

 two kilometers the road cuts through this range of tertiary limestone 

 hills, which have an altitude of six hundred feet. At Serba Mocha the 

 peculiar limestone hills known as the Pan de Matanzas are seen to the 

 north across an eroded valley. These summits are to the western half 

 of the island what the Yunque is to the eastern, — remarkable isolated 

 remnants of the nearly destroyed older levels which once surmounted 

 tlie island. The Pan de Matanzas is alleged to be twelve hundred feet 

 high. It consists of a double eminence, the intervening valley present- 

 ing precipitous walls. The summits are of limestone, and are clearly 

 remnants of the old limestone mass of the interior, from which they have 



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