154 RAMBLES OF A NATURALIST. 



whose existence had never before been suspected. 

 He found that the mud, forming the lowest stratum, 

 and which is almost always black and fetid, was 

 often interspersed with numerous skeletons of bears, 

 hyenas, and sometimes even of dogs, wolves, and 

 jaguars, belonging to species of much larger size than 

 their existino; congeners. The bones of Ruminants 

 and Rodents, and often too, those of Birds and large 

 Pachyderms were blended with the bones of these 

 carnivorous forms, and we can still trace the marks 

 on their surfaces of the terrible teeth by which 

 they were broken. These circumstances led Dr. 

 Buckland to the conclusion that caverns of this kind 

 had probably been used as places of resort both by 

 the carnivorous animals, whose remains have been 

 preserved in them, and by the victims which once 

 served to appease their hunger. This very plausible 

 explanation was generally received, and did not for a 

 long time meet with any decided contradiction. 



Science, however, speedily recorded other facts, 

 which could not be made to harmonise with the 

 theory of the English geologist. It was discovered 

 that rocks of compact limestone, whose mass presented 

 no trace of fossils, w^ere yet traversed by veins which 

 were entirely filled with bones, impacted in a 

 matrix differing entirely from the rock itself. These 

 veins very frequently presented no appearance of 

 any lateral aperture, while the debris contained 

 within them in some instances completely filled 



and on meeting they become joined together. It is this mode of 

 deposition which gives rise to those beautiful colonnades which are 

 found in certain grottoes. 



