P. BECKLESII AND P. MINOE. 429 



the tanks, or wherever running water falls into an artificial 

 lake, numerous remains may be observed, along the margin, 

 of the bones of frogs, lizards, mice, and musk rats, forming a 

 more or less continuous edging, without the admixture of 

 large bones, which lie in abundance below the deeper water. 

 The former float and are drifted to the margin by the action 

 of the wind, and rest there. 



M. Lartet pointed out to me, in the rich Falun ian deposit 

 of Seissan, certain parts of the Lacustrine bed where skele- 

 tons of large terrestrial animals, such as Mastodon and Rhi- 

 noceros, are more or less abundant ; while in other situations 

 near the margin immense quantities occur of the bones of 

 small animals, such as frogs, lizards, shrews, and minute ro- 

 dents, which may be taken up by the handful unmixed with 

 larger bones. The mammaliferous band, ' ~No. 93,' where 

 most productive, does not exceed five inches in thickness. If 

 the excavations could be carried into a line of section where 

 the bed is thicker, it does not seem too much to hope that 

 they might be rewarded by the discovery of larger mammals, 

 when we consider the numerous accraisitions to Palaeontology 

 which have been made within the last two months alone 

 from Purbeck, and the improbability that a fauna already 

 proved to have been so extensive should have been restricted 

 to small creatures only. Further, where herbivorous mam- 

 mals are shown to have existed, it would seem in the highest 

 degree improbable that they should have been limited to a 

 single genus containing two small species like Plagiaulax. 



