NOTES ON THE GEOLOGY OF THE BAHAMAS 37 



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 horizon- 

 tal 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 depressions 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 cylindri- 

 cal 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 very great. If 

 we could have a good view of the proper bottom of a banana hole, we 

 might be able to account for their formation; but, unfortunately, the 

 bottom is always filled with a deposit pf earth or blocks of coral rock, 

 and generally covered with Vegetation.' 



It is not improbable that the deep cylindrical ones were formed in 

 the same manner as pot-holes. And others might have originated in 

 the same way as the spouting holes, where the waves undermine the 

 shore and afterward break an opening in the rock above. Should 

 some of the boiling holes, described above, become elevated and their 

 bottoms filled up with fallen blocks of coral rock and deposits of earth, 

 they would form banana holes. The holes in the cracks at Fresh Creek 

 can be easily explained, but if all banana holes were formed in this 

 manner, we should find them in a line with others, which I was told was 

 the case, but I was never able to satisfy myself that it was so. The 



• Proc. Acad. Nat. Sci. Philadelphia, 1889, p. 132. 



