30 Mr. R. C. Taylor's Notes relative to the Geology of Cuba , 



of which the apertures are nearly closed up. All these cham- 

 bers have nearly level floors, covered to an unknown thickness 

 with red earth or mould, on which is thickly strewed the dung 

 of the thousands of bats which congregate here, and myriads of 

 snail-shells. I think the dung of the bats alone would be in 

 sufficient quantity to account for the red earth, and that the 

 colouring matter of this earth and of the rock into which it 

 passes is vegetable and not mineral, as the examinations to 

 which it has been submitted appear to determine. We would 

 have ascertained the depth of this soil on the floor of the cave, 

 but the annoyances from the causes alluded to rendered our 

 stay there almost impracticable. We ascertained quite enough, 

 however, to feel assured that in this soil, to which the bats 

 have largely contributed and have coloured by some vegetable 

 exuviae, — in the multitude of dead and decomposing shells, for 

 which this cave seemed the charnel-house, the tomb of mil- 

 lions, — in the gradual conversion of this mass to the state of 

 solid rock, we saw the origin of those beds of shelly carbonate 

 of lime which at first sight seemed almost inexplicable. 



Admixture of Terrestrial, Marine, and Freshwater Shells, — 

 The shores of the bay of Gibara supply to the geologist an 

 instructive instance of this association of shells of different 

 habits. There are several streams which empty themselves 

 into this bay, and which in times of floods, during the rainy 

 season, bring down an immense number of dead land-shells 

 from the high lands of the interior. We here noticed ex- 

 tensive banks -or deposits of terrestrial and marine shells, 

 as on the mountain of La Silla; but the agency is re- 

 versed. In the one case we saw that the marine shells were 

 conveyed by those active agents the soldier crabs even to 

 the highest crest of La Silla. In the other the land shells 

 have been brought down from the rocky recesses of La Silla, 

 and are deposited in multitudes with those of the sea, on the 

 margin of the estuary. Were any great geological catastrophe 

 to occur, by which these accumulations would be buried, and 

 be subjected to the examination in future times of some in- 

 quiring naturalist, he would see repeated here the phenomena 

 which have been observed in more than one position in re- 

 mote parts of the globe : with these he would find also a full 

 proportion of freshwater shells, but of one genus and species 

 only, the inhabitants of the Cuba streams, the Neritina vir- 

 ginea of Lamarck ; of which great quantities are brought down 

 by the freshes and deposited on the beach with the terrestrial 

 and sea shells, and with the small oysters which cluster so 

 thickly on the pendent branches of the mangroves of the 

 creeks. 



