72 REPORT — 1842. 



Genus Lutra. 



Of this genus I have determined characteristic remains of a species about 

 the size of the common Otter, in the so-called mammaliferous crag at South- 

 wold, and near Aldeburg, Suffolk. 



Order Cetacea. 



Most of the remains of this order of Mammalia, have been, in Great Britain 

 found in gravel-beds adjacent to estuaries or large rivers, in marine drift or 

 diluvium, and in" the subjacent clay-beds : but although these depositories are 

 the most superficial, and belong to the most recent period in geology, the 

 situation of the cetaceous fossils generally indicate a gain of dry land from 

 the sea. Thus the skeleton of a Balsenoptera, 72 feet in length, found im- 

 bedded in clay on the banks of the Forth, Mas more than twenty feet above 

 the reach of the highest tide. Several bones of a whale, discovered at Du- 

 more Rock, Stirlingshire, in brick-earth, were nearly forty feet above the 

 present level of the sea. The vertebrae of a whale, discovered by Mr. Richard- 

 son in the yellow marl or brick-earth of Heme Bay, in Kent, were situated 

 ten feet above the occasional reach of the sea on that coast. A large verte- 

 bra of Balccna mysticelus was discovered fifteen feet below the surface, in 

 gravel, by the workmen employed in digging the foundation for the new 

 Temple Church. The teeth of a Cachalot have been discovered by Mr. Brown 

 in the diluvium of Essex. Part of the tusk of a Narwhal (Alonodon) has 

 been discovered in the London clay ; presenting the usual condition of the 

 fossils*from that old tertiary stratum. 



The most completely petrified remains of this order are a series of anchy- 

 losed cervical vertebra? of a large Delphinns in the museum of Prof. Sedg- 

 wick. Their fossilized condition indicates a higher antiquity than the Ceta- 

 cean fossils above noticed : they were discovered in Cambridgeshire, but the 

 stratum and locality were unfortunately unknown. 



No specimens of herbivorous Cetacea have hitherto been discovered in 

 British strata. 



Order Rodentia. 



The British fossil remains of species of this order hitherto detected are 

 referable to the genera Castor (Beaver), Arvicola (Water-vole, Field-vole), 

 Mils (Rat and Mouse), and Lepus (Hare and Rabbit); which have been 

 found in superficial drift, bogs and fens, (Castor), in bone-caves, in the 

 brick-earth deposits, in the mammaliferous crag, and in the subjacent red 

 crag. The ancient Rodents from the last two tertiary formations belong to 

 the genus Arvicola. The fossils of the Beaver above noticed agree with the 

 species of the Danube. Besides these, the remains of the great Castor Tro- 

 gontherium have been found in the submarine forest at Bacton. 



Order Marsupialia. 

 Genus Didefphi/s ? 

 In the eocene sand, underlying the London clay, at Kyson near Wood- 

 bridge, Sussex, a small portion of jaw, with a spurious molar tooth, has been 

 found. This fossil has been referred to the Opossum (Diddphys), but the 

 evidence which it afforded is, in my opinion, insufficient to support that con- 

 clusion. There is no tooth so little characteristic, or upon which a deter- 

 mination of the genus could be less safely founded, than one of the spurious 

 molars of the smaller carnivorous and omnivorous Ferce and Marsupialia. 

 A large, laterally compressed, sharp-pointed middle cone or cusp with a small 

 posterior, and sometimes also a small anterior talon, more or less distinctly de- 

 veloped, is the form common to these teeth in many of the genera of the above 



