224 



HISTORICAL PALAEONTOLOGY. 



are now exclusively confined to the Australian province, South 

 America, and the southern portion of North America. In 



.'^ 



Fig. 15S. — The Banded Ant-eater {Myrjiiecobius fasciatns) of Australia. 



the Old World, the only known Triassic Mammals belong to 

 the genus Microlestes, and to the probably identical Hypsi- 

 pry7niiopsis of Professor Boyd Dawkins. The teeth of Micro- 

 lestes (fig. 157) were originally discovered by Plieninger in 

 1847 in the ''bone-bed" which is characteristic of the sum- 

 mit of the Rhaetic series both in Britain and on the continent 

 of F.urope ; and the known remains indicate two species. In 

 Britain, teeth of Microlestes have been discovered by Mr 

 Charles Moore in deposits of Upper Triassic age, filling a 

 fissure in the Carboniferous limestone near Frome, in Somer- 

 setshire ; and a molar tooth of Hypsipryvinopsis was found by 

 Professor Boyd Dawkins in Rhaetic marls below the " bone- 

 bed " at Watchet, also in Somersetshire. In North America, 

 lastly, there has been found in strata of Triassic age one of 

 the branches of the lower jaw of a small IMammal, which has 

 been described under the name of Dromatlm-iiini sylvesire 

 (fig. 156). The fossil exhibits ten small molars placed side 

 by side, one canine, and three incisors, separated by small 

 intervals, and it indicates a small insectivorous animal, pro- 

 bably most nearly related to the existing Myrmecobhis. 



Literature. 



The following list comprises a few of the more important sources of 

 information as to the Triassic strata and their fossil contents :— 



(i) * Geolog)' of Oxford and the Valley of the Thames.' Phillips. 



(2) 'Memoirs of the Geological Survey of Great Britain and Ireland.' 



(3) 'Report on the Geology of Londonderry,' &c. Portlock. 



