224 PROCEEDINGS OP THE QEOLOGICAI, SOCIETY. [Feb. 8, 



It is only in such deposits as the older sandstones, which have been 

 in a great measure altered, or in clays where water can accumulate, 

 that heavy and thoroughly mineralized specimens are formed. 



If, bearing these facts in mind, the fossil Mammalian remains 

 of the Red Crag are examined, a very important light may be 

 thrown on the origin of their association. With the exception of a 

 few very rare, fragile, and indeterminable pieces of bone, all the 

 Mammalian fossils of the Eed Crag are very heavy, compact, 

 thoroughly mineralized, and indurated. This induration could not 

 have taken place in the Crag Sea whilst these remains -were fresh, nor 

 in the Crag afterwards ; hence it is inferred that the specimens were 

 washed from previous strata, and that those not destroyed by rolling 

 and water-action were thoroughly imbued with salts of iron. No 

 specimen of bone from the Crag is free from evidence of much 

 rolling and washing as though on a sea-beach, and all are discon- 

 nected and fragmentary : the so-called Coprolites, now acknowledged 

 to be concretionary nodules, often when in situ show fractures across 

 their former centres of concretion, with worn edges ; so that semi- 

 circular and rectangular pieces often occur. These facts again point 

 but to one conclusion with regard to the association of the Mam- 

 malian fossils. Sharks' teeth, and phosphatic nodules with the Mol- 

 luscan fauna of the Crag; and it is that the sea in which the 

 Molluscan fauna Uved broke up various previous Phocene, Miocene, 

 and Eocene beds, and appropriated some of their organic contents. 



It is allowed by most geologists that this is the case as far as 

 concerns the teeth of Coryphodon, Otodus, Lamna, (fee, and the 

 phosphatic masses, which all occur in abundance in the Lower 

 Eocene clays of Sheppey ; and the same reasoning should apply in 

 the case of the Ziphioid Cetaceans and Miocene Mammaha which 

 occur so abundantly in the earlier strata of Antwerp and Darmstadt 

 in an unrolled condition. 



■ There is, however, further evidence of the derivative nature of 

 these two latter groups of remains. Eractured specimens occur of 

 Cetacean bones and teeth which must have been broken subse- 

 quently to their partial fossUization, on the broken surfaces of which 

 " Balani " of Crag species are attached. A dark indurated matrix, 

 totally differing from the Red Crag, and resembling the Middle 

 Antwerp deposit, frequently surrounds the Cetacean teeth ; it could 

 only have been attached to the teeth by their having previously 

 been imbedded in such a deposit as that of Antwerp. The teeth 

 of the Mastodon and the Rhinoceros, again, frequently contain in 

 their interstices and cavities a light-coloured fine matrix, which 

 must have been obtained by their deposition in an earlier bed totally 

 differing from the Red Crag. 



On the following grounds, then, it seems fair to conclude that 

 the Mammalian fossils of the Red Crag are mostly derived from 

 earlier beds — the Ziphioid Cetaceans (with Carcharodon, &c.) from 

 an equivalent of the Middle Antwerp Crag, the Mastodon, Rhi- 

 noceros, Tapir, Sus, Felis, &c. perhaps from a late Miocene, or more 

 probably from an early Pliocene bed : — 



