1890.] NEW YORK ACADEMY OF SCIENCES. 13 



of earth in the bottom, in which the natives plant their bananas, 

 and hence the name. 



In shape and dimensions these holes vary greatly. Some are 

 cylindrical, abont four feet in diameter, but at the same time 

 twenty feet or more in depth. Others are from ten to twenty- 

 five feet across, and some even larger, and often of an irregular 

 shape and mucli longer than wide. 



The walls are often excavated below, so that the side becomes 

 an overhanging ledge and forms a small cave. In some a cave 

 begins at the side of the hole and runs backward. It is hence 

 hard to draw the line between these holes and the caves. There 

 are also holes that are not called banana-holes, but which may 

 be here described, as they differ only in shape. In some the 

 opening is barely large enough to allow a man to pass. One 

 such I descended, and found that below it was over five feet in 

 diameter and cylindrical. The top had been excavated so as to 

 form a domed roof. 



Other holes were connected by a horizontal passage through 

 which I could crawl from one to the other. One of these I saw 

 near Conch Sound, where the passage ran from the bottom of 

 one hole to the side of the other, which was much deeper. 



Near by I saw two shallow holes that were connected by a 

 horizontal passage, so that they resembled a large tube bent up 

 at each end. It is not unusual to find openings in the ground, 

 barely large enough to admit an ordinary pail, and sometimes 

 much smaller. These are simply openings in the roof of a cave 

 or hole of unknown dimensions, and frequently in the bottom 

 is a quantity of fresh water that is used by the people. 



The subject of banana-holes has been briefly discussed by Dr. 

 C. S. Dolley,' who accounts for their formation by " the action of 

 decaying vegetable matter, that undergoes fermentative changes 

 by the products of which the soft, calcareous rock is dissolved 

 and leaches away." There is no doubt that the rock is in many 

 places eroded in this manner, as the small, saucer-shaped depres- 

 sions so common on the surface, and each often containing 

 leaves and water, plainly testify. But I doubt if this agent alone 

 would cause the deep vertical cylindrical holes, or those in 

 which the sides recede into caves or the horizontal passages. 

 And if the holes were formed in the manner described by Dr. 

 Dolley, should we not find them in the low level land as well as 

 on the ridges ? But, as stated before, the holes are found in far 

 greater number on the ridges, and in places where the surface is 

 such as to indicate that formerly the erosion from the waves was 



'Proc. Acad. Nat. Sci., Phila., 1889, p. 132. 



