224 HISTORICAL PALA ONTOLOGY. 
are now exclusively confined to the Australian province, South 
America, and the southern portion of North America. In 
ean ee a 
Fig. 158.—The Banded Ant-eater (1/yrmecobius fasciatus) of Australia. 
the Old World, the only known Triassic Mammals belong to 
the genus AZicrolestes, and to the probably identical Aypsz- 
prymnopsis of Professor Boyd Dawkins. The teeth of JZcro- 
lestes (fig. 157) were originally discovered by Plieninger in 
1847 in the ‘‘ bone-bed” which is characteristic of the sum- 
mit of the Rheetic series both in Britain and on the continent 
of Europe ; and the known remains indicate two species. In 
Britain, teeth of JZicrolestes 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 Hypsiprymnopsis was found by 
Professor Boyd Dawkins in Rhetic 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 Mammal, which has 
been described under the name of Dromatherium sylvestre 
(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 AZ7yrmecobius. 
LITERATURE. 
The following list comprises a few of the more important sources of 
information as to the Triassic strata and their fossil contents :— 
(1) ‘ Geology 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. 
