1865.] LANKESTER CRAG MAMMALIA. 225 



1st. The occurrence of the Mammalian remains in question else- 

 where, separately, and in widely different formations. 



2nd. The improbabiUty of the coexistence of several Mammals of 

 Miocene and early Pliocene " facies " with a Molluscan fauna shown 

 elsewhere to be of late Pliocene origin. 



3rd. The rounded, washed, and worn nature of the specimens, as 

 well as their rarity and fragmentary character. 



4th, The complete mineraUzation of these fossils, their hardness 

 and great weight, which tend to prove their derivative nature, 



(1st) Because the proper fossils of the Crag are light, unminc' 

 ralized, disintegrated, and pulverulent. 



(2nd) Because specimens known to be derived are heavy and 

 hard, as these are. 



(3rd) Because a loose sand, such as the Crag, cannot produce the 

 complete induration of specimens. 



5th. The very frequent presence of attached marine organisms of 

 the Crag age on the broken surfaces of these specimens. 



6th. The occurrence of a matrix surrounding the teeth differing 

 entirely from the Bed Crag. 



In addition to the considerations thus stated, there is, with regard 

 to the terrestrial Mammalia, the very important fact that the teeth 

 of Mastodon and Rhinoceros of the same species as the Red Crag 

 forms have been found at the base of the Coralline Crag, associated 

 with phosphatic nodules and other debris, which leaves very little 

 room for doubt that, whatever species they may be identical with, 

 the Mastodon, Bhinoceros, and other molars are derived from beds 

 of a period previous to the Bed Crag era. Por these reasons I 

 would urge the probability of a previous extension of the Middle 

 Crag of Antwerp *, and also possibly of the earlier PKocene or late 

 Miocene deposits of North Eui'ope, along their natural horizon to 

 the line of the present coast of Suffolk — an extension which does 

 not prima facie appear at all imlikely or impossible. From the 

 Middle Crag beds, then, the Ziphioid and other Cetacean remains 

 were derived ; from the Miocene or early Pliocene, the terrestrial 

 Pachyderms ; from our own Tertiaries, the Coryplwdon, Hyracoihe- 

 rium, &c. The appended Table may be of assistance in explaining 

 the relations of the various strata. The percentages of Mollusca 

 are compiled from the various publications of Mr. Wood and Mr. 

 Nyst ; and perhaps in some cases either or both of these gentlemen 

 have been too prone to establish new species distinct from recent 

 forms, which makes the percentage of living Mollusca appear un- 

 usually small. 



The remarks made in the foregoing pages must be considered 

 merely as an extension or modification of views which have been 

 formerly advanced, chiefly by Mr. Searles "Wood, sen., who, in 1859, 

 published a valuable paper on the extraneous fossils of the Bed 

 Crag, in which, however, less conclusive evidence was adduced f. 



* On these beds, see my paper in the Geological Magazine, vol. ii. pp. 103 & 

 149, 1865. 

 t Since this paper was read, Professor Owen lias forwarded me an absti'act 



r2 



