196 



BLIND VERTEBRATES AND THEIR EYES. 



various caves, together with the elevations of the mouths of the caves, we get the 

 following results: 



The elevations of the water of the caves together with the well at the house 

 Isabella fall into two groups : first, those from numbers 1 to 8 in which the elevation 

 of the water does not vary more than 11 feet. This amount may easily be due to 

 change in barometric pressure during the various readings and to the personal equa- 

 tion. It seems probable that the water in these caves, most of which are south of 

 Finca Isabella, is at a level, and that this level is between 8 and 19 feet above sea- 

 level. The Finca Isabella is about 15 miles north from the coast, or 10 miles from 

 the Cienaga, in which some of the underground rivers rise to the surface. 



The second group, from 9 to 12, are east of Isabella; 9 and n are near each 

 other; 12 is 2 miles or more east of 9 and 11, and I am not certain about the loca- 

 tion of 10. These readings were taken August 25, 1903, in the order: 10, 12, n, 9. 

 The first reading at the house was at 6 h 3o m a. m., when the barometer stood at 

 1,114 feet. The trip consumed all of the morning. About 3 p. m. the barometer 

 stood at 1,179 at the house, so it is very probable that the high elevations may in 

 part be due to the change in barometric pressure. 



For comparison we have the data for the caves, Adolfino and Insurrectos, at the 

 Carboneria, near the north coast. 



The Cave of the Insurrectos is about 93 feet above sea-level according to barom- 

 eter. The water is 83 feet below the surface and according to that 10 feet above sea- 

 level. 1 



The top of Adolfino is 87 feet above sea-level, the water is 80 feet below, or 7 

 feet above sea-level. The surface of the Carboneria well is about 4 feet above 

 sea-level, the surface of the water is at sea-level and more than 5 feet deep. 



There is every indication that the water has risen about 10 feet in the caves 

 in very recent geologic times. In all the caves stalagmites are seen to rise out of 

 the water, in some cases from a depth of at least 10 feet. As these could only have 

 been formed on ground free from water it is evident that the water must have risen 

 in the caves. As the water is now near sea-level, this rise is probably due to the 

 subsidence of the western end of the Island of Cuba. This subsidence is general, as 

 stalagmites are found submerged on the northern and southern sides of the island. 



1 The water in the Donkey and" M "caves, according to barometric readings from the railroad station at Union, 

 is below sea-level. It is not at all probable that this reading is correct, but it indicates that the groundwater 

 level is here again very near sea-level. At " M," according to barometric reading, it is 83 feet below the gen- 

 eral level of the surface and at the Donkey it is 73. 



