190 PLEISTOCENE MAMMALIA. 



the latter, as well as in the canine (incisor ?), renders it probable that all the teeth of this 

 species were serrated. 



§ 8. Antiquity in Kent's Hole. — We have now to consider the very difficult question 

 as to the relative antiquity of the Machcerodus latidens in Great Britain. Is it Pleiocene 

 or is it Pleistocene ? Was it a contemporary of the woolly Mammoth and Reindeer, or 

 had it disappeared before the lowering of the temperature in the Glacial period ? Unfor- 

 tunately the peculiar physical conditions under which Kent's Hole has been filled with 

 its present contents forbids an answer which is absolutely decisive. In the present cave- 

 earth, and underneath the stalagmite which now constitutes the floor, are large masses of 

 breccia and of stalagmite, which evidently had formed a floor that had been broken up 

 before the introduction of the cave-earth. They are remarkable for their hard crystal- 

 line structure, and in one or two cases they have yielded fragments of very dense 

 mineralized bones. In a portion of the cave, called the gallery, there is evidence of the 

 undisturbed portion of the crust in a "ceiling" or uppermost floor, that extended from 

 wall to wall, " without further support than that afforded by its own cohesion. Above 

 it there is, in the limestone rock, a considerable alcove. This branch of the cavern, 

 therefore, is divided into three stories or flats ; that below the floor occupied with cave- 

 earth, that between the floor and ceiling entirely unoccupied, and that above the 

 ceiling also without a deposit of any kind." For a ceiling of this kind to have been 

 formed it is absolutely necessary for the cave to have been rilled up to its level with 

 materials of some kind. It would, indeed, be as impossible for a solid calcareous sheet 

 to be formed in mid-air as it would be for a sheet of ice to be formed without resting on 

 water. From some cause or other this ancient stalagmite has been in part broken up, 

 and the materials by which it has been supported have disappeared ; and that it was 

 deposited on cave-earth, like that now occupying the lowest story, is shown by Its red 

 colour. Prior, however, to its formation, animals dwelt in the cave, since bones are 

 imbedded in the large fallen masses of stalagmitic breccia. Moreover, there is reason to 

 believe that certain fragments of bone and splinters of teeth, remarkable for their 

 mineralization, that have been found in the earth now occupying the cavern, were 

 derived from this more ancient deposit, for they differ essentially from the remains with 

 which they are now associated, being heavier and of a more crystalline structure. Some 

 splinters have assumed the fracture of greensand-chert. So hard, indeed, was one of 

 the canines of Bear that it has been splintered by the hand of man into the form of a 

 flint-flake, and has evidently been used for a cutting purpose. Its fracture proves that 

 it was mineralized before it was splintered ; and as it was found in the present cave- 

 earth, it must have been fashioned while the cave was being inhabited by palaeolithic 

 man, prior to the accumulation of the earth. For these reasons, the evidence in favour 

 of these denser remains having belonged to the deposit which once supported the ancient 

 floor seems to us incontrovertible. 



