216 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



the limestone rocks has been an important factor in shaping the general 

 plane of the region. No one can find their way any distance into the 

 Everglades without being struck with the deeply corroded and honey- 

 combed aspect of the rocks, and the numerous sink-holes, due to the 

 effect of the rain water saturated with acids derived from the decaying 

 vegetable matter. 



Heilprin has well shown that the lagoons and sounds of the Ber- 

 mudas are not kept open through solution, and do not owe their origin 

 or increase to that cause. 1 But I think he has underestimated the effect 

 of solution on the cliffs and ledges where exposed to the action of the sea. 

 The solution effected by the percolation of fresh water is clearly seen in 

 the sinks, 2 pot-holes, and caverns opening out on all the cliff exposures 

 and in many of the cuts in the honeycombed surfaces of the seolian 

 rocks wherever laid bare. There is hardly a vertical wall or cut for a road 

 which does not show some trace of the solvent action of water percolat- 

 ing through the ssolian beds and covering patches of the edges of the 

 strata with a stalagmitic coating, so as to obliterate their dividing lines 

 or form small stalactites from bed to bed. 



A comparison of the base of the sea faces of the cliff ledges with the 

 sides of the mushroom-shaped rocks below low-water mark will clearly 

 indicate the different kind of work accomplished by solution by sea 

 water acting upon the more or less submerged vertical faces, and that 

 exhibited by the action of fresh water some yards above the high-water 

 mark. The effect of the solvent action of the sea water is readily traced 

 above the high-water mark as far as the waves or spray can reach, and 

 the encroachment of the sea water upon the area partly honeycombed by 

 fresh water is most instructive (Plates XXVIII. , XXX.). Above high- 

 water mark the area exposed to this action is very considerable, and by 

 the solvent effects of sea water upon the limestone area exposed be- 

 No. 7, 1890, p. 145. See also Murray and Irvine on Coral Reefs and other Car- 

 bonate of Lime Formations in Modern Seas, Proc. R. Geog. Soc. Edinb., 1889-90, 

 Vol. XVII. p. 79. 



1 Bermudas, p. 44. 



2 Professor Dolley accounts for the formation of banana holes by the action of 

 decaying vegetation collected in the holes, kept moist by the action of rains under- 

 going fermentative changes by the product of which the soft calcareous rock is 

 dissolved and leaches away. This process undoubtedly acts as suggested by Pro- 

 fessor Dolley, but only to a limited extent, as the most active honeycombing takes 

 place on the surface of barren islands, where the vegetation has long ago disap- 

 peared, but where the surface is exposed to the combined action of rain and of salt 

 water spray, as at Glass Window, Great Isaac, and other places in the Bahamas. 

 See A. Agassiz, Bull. Mus. Comp. Zo.il., Vol. XXVI. No. 1, 1894, pp. 30, 60. 



