522 



BUEYINa OF FOSSILS IN 



[Ch. XLY. 



tlie scar-limestone, a member 



of tlie carboniferous series. 

 ' The chasm,' says Professor Sedgwick, ' is surrounded by 

 grassy shelving banks, and many animals, tempted towards 

 its brink, have faUen down and perished in it. The approach 

 of cattle is now prevented by a strong lofty wall ; but there 

 can be no doubt that, during the last two or three thousand 

 years, great masses of bony breccia must have accumulated 

 in the lower parts of the great fissure, which probably 

 descends through the whole thickness of the scar-limestone, 

 to the depth of perhaps five or six hundred feet.' * 



When any of these natural pitfalls happen to communicate 

 wdth lines of subterranean caverns, the bones, earth, and 

 breccia may sink by their own weight, or be washed into the 



vaults below. 



extremity 



pendicular fissures, on the ledges of which a number of 

 hawks nestle and rear their young in the breeding season. 

 They throw down from their nests the bones of small birds, 

 mice, and other animals on which they feed, and these are 

 gradually united into a breccia of angular fragments of the 

 decomposing limestone with a cement of red earth. 



At the pass of Escrinet in France, on the northern escarp- 

 ment of the Coiron hills, near Aubenas, I have seen a breccia 

 in the act of forming. Small pieces of disintegrating lime- 

 stone are transported, during heavy rains, by a streamlet, to 

 the foot of the declivity, where landshells are very abundant. 

 The shells and pieces of stone soon become cemented together 

 by stalagmite into a compact mass, and the talus thus formed 

 is in one place 50 feet deep, and 500 yards wide. So firmly 



mill 



stones. 



if Cuba. — One of 



most 



singular examples of tlie recent growth of stalagmitic lime- 



Mr 



Taylor^ as observable on the nortli-east part of the island of 

 Cuba.f The country there is composed of a white marble, 

 in which are numerous cavities, partially filled with a cal- 



- 



* On the Lake Mountains of North f Notes on Geol. of Cuba, 1836, 



of England, Geol. Soc, Jan. 5. 183i. Phil. Mag., July, 1837. 





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