THEIR GEOLOGICAL AGE. 197 



stow, exists in the Geological Society's collection ; there are 

 others in the Museum of Practical Geology, and in various col- 

 lections in Norfolk which I have examined. Of Loxodon meri- 

 dionalis a very characteristic and decisive specimen is repre- 

 sented in the 'Fauna Antiqua Sivalensis' (Plate XIV. B. figs. 

 18 and 18 a). 1 It was discovered in the Mammaliferous Crag 

 near Harwich, and consists of the last lower molar, right 

 side, having twelve ridges, along a length of twelve inches. 

 The ridges are comparatively low, their height, where intact, 

 not much exceeding the width of the crown. The dictations 

 are thick and distinct for a considerable distance below their 

 apices ; and the plates of enamel very thick. The ridges are 

 so thick that they average one to an inch. In the aggregate 

 the characters approach very closely to those of the equi- 

 valent teeth in Loxodon planifrons of the Sewalik hills. The 

 specimen is highly ferruginous, like most of the Crag bone- 

 remains. Two other specimens, which I have examined from 

 the Crag, presented by Miss Anna Gurney to the Paris 

 Museum, are figured by De Blainville. They are 'inter- 

 mediate molars ' of Loxodon meridionalis. Various other 

 illustrations might be cited, but I confine the references to 

 figured specimens. These Crag specimens respectively of 

 Loxodon meridionalis and Euelephas antiques differ in no 

 material respect from specimens of the same species above 

 referred to as occurring in the Italian Pliocenes. 



The highest level in which Tetralophodon Arvernensis occurs 

 in British strata has not yet been accurately ascertained. In 

 the remarkable case of the entire skeleton recorded by Mr. 

 Layton as having been discovered at Horstead, ' stretched 

 out between the chalk and the gravel,' it has not yet been 

 clearly made out whether the bed is an equivalent of the 

 Crag or above it. The locality has been examined conjointly 

 by Messrs. Godwin- Austen, Prestwich, and Morris ; and Mr. 

 Austen assures me that there is no doubt about the authen- 

 ticity of the case, and that the skeleton was certainly of a 

 Mastodon. The bones of the herbivorous mammals occurring 

 in the Crag are invariably presented in a condition more or 

 less fragmentary, as if they had been washed out of a pre- 

 existing Pliocene land and deposited in a reconstructed sea- 

 bottom. A slight oscillation of the relative levels of the land 

 and sea would admit of this being effected within a com- 

 paratively limited period. Having regard to the undisturbed 

 and compact state in which the Horstead skeleton lay, it may 

 be inferred that the deposit was either on a higher level than 

 the Crag, or that the breaching action of the Crag-waves had 



1 Sco vol. i. p. 447, and vol. ii. PL viii. fig. 1. — [Ed.] 



