ROOM IV. FOSSIL MAMMALIA OF STONESFIELD. 405 



whose term of existence seems fast waning to its close. 1 Pro- 

 fessor Owen concludes with the following remark : " Con- 

 necting the close resemblance which the molar teeth of the 

 Phascolotherium bear to those of the Thylacine, with the simi- 

 larities which have already been shown to exist in the several 

 characteristic features of the ascending ramus of the jaw, 

 I am of opinion that the marsupial extinct genus indicated 

 by the Stonesfield fossil, was nearly allied to Thylacinus, 

 and that its position in the marsupial series is between Thyla- 

 cinus and Didelphys." 2 



GEOLOGICAL INFERENCES. From what has been stated, it 

 is evident that these mammalian remains from Stonesfield 

 prove the existence at the commencement of the Oolitic 

 period, of the two grand divisions of the class Mammalia, 

 namely, the marsupial, and the placental. Commenting on 

 this remarkable fact, Sir Charles Lyell observes, that "the 

 singular accident of our having as yet found nothing but the 

 half of the lower jaws of seven individuals, and no other bones 

 of the skeleton, is alone sufficient to demonstrate the frag- 

 mentary manner in which the memorials of our ancient 

 terrestrial fauna are handed down to us. We can scarcely 

 avoid suspecting, that the two genera above described may 

 have borne a like insignificant proportion to the entire assem- 

 blage of warm-blooded quadrupeds which nourished in the 

 islands of the oolitic sea." 3 



1 "British Fossil Mammals," pp. 64, 65. 



2 Ibid. p. 67. 



3 "Manual of Elementary Geology," p. 270. This eminent philo- 

 sopher, in his late Address on retiring from the chair of the Geological 

 Society, again adverts to this important fact. " Yet no small diligence 

 has been used by collectors for more than a quarter of a century to 

 obtain even the smallest isolated bones from these beds. I can only 

 compare the capricious chance which has hitherto put us in exclusive 

 possession of these seven mammalian jaws, with the equally strange 

 accident recorded by Dr. Mantell in his career of discovery in the 

 AVealden. He computed that in the course of 20 years he had found 

 teeth and bones of the Iguanodon which must have belonged to no less 

 than 70 distinct individuals, varying in age and magnitude from the 

 reptile first burst from the egg, to one of which the femur measured 24 

 inches in circumference. Yet it was not until the relics of all these 

 individuals were known, that a solitary example of part of a jaw-bone 

 was obtained." Address delivered at the Anniversary Meeting of the 

 Geological Society of London, Feb. 21, 1851, by Sir Charles Lyell, FM.S. 

 p. 49. 



