CHAP. XIV.] THE CAT'S HEXICOLOGY. 501 



region may be considered as a sort of negative feline region, the 

 emphatically " catless " portion of the globe. 



§ 6. We must next consider the relations of cats to Time, and 

 first with respect to individual life. The cats of largest size appear 

 to live longest. The domestic cat lives ordinarily for about twelve 

 years, and eighteen years is the greatest age for Avhich the Author 

 has obtained certain evidence. The lion is said however to live for 

 forty years, and the well-known lion named "Pompey," which died 

 in the Tower of London in 1760, had lived there, it is asserted, for 

 no less than seventy years. This seems, however, to be a fable. 

 The Author has not been able to ascertain with certainty that the 

 lion lives beyond thirty years. 



As to the period during which existing kinds of cats have lived 

 in times geologically recent, we must have recourse to history and to 

 deposits such as those amongst which have been found the prehistoric 

 remains of earlier races of man. As to the existence of Fclidce in more 

 ancient periods, and as to the period when genera which are now 

 extinct flourished, evidence has to be sought for amongst the fossils 

 contained in the rocks and deposits of difl'ercnt geological dates. 



It has already been said that lions existed in South-eastern 

 Europe in the time of Xerxes. These may have been survivors of 

 the huge cat Felis spelea (the so-called cave lion). But whether 

 this was the case or not, it is certain that large extinct kinds, 

 together with the leopard and other smaller forms (including the 

 wild cat), ranged over Europe and England in prehistoric periods of 

 very different dates. 



§ 6. Before passing in review those genera of cats which have 

 become extinct, it may be well to state briefly some elementary facts 

 of geology, an acquaintance with which is necessary for a correct 

 appreciation of the relation of the cat to past time. 



Tbe outer crust of the earth consists of more or less horizontal 

 layers of different materials deposited from salt or fresh water, and 

 known as strata. In these are often contained evidences of past 

 animal life in the shape of (1) real bones, (2) pseudomorphs or 

 aggregations of mineral matter which have exactly taken the place 

 of real organic objects which have disappeared, (3) moulds external 

 or internal, or (4) casts of moulds of such objects — all these four 

 kinds of relics being what are called " fossils." 



The various "strata" were of course deposited at successive 

 times, and the time of the deposition of each is called its " period," 

 or "epoch." But for subsequent disturbance, the most ancient 

 strata would always be, as they generally are, the deepest. 



The uppermost and most recent accumulations of sands, clays, 

 and gravels form what are called the " recent deposits," and these are 

 not counted as forming any part of the proper geological strata. 



The strata beneath these are classifled in three great groups, 

 belonging respectively to three great epochs. 



The first or uppermost, and least ancient group, consists of strata 

 called the tertiary or cainozoic strata. 



