124 



THE OLDEST MA.MMALS. 



mouth is armed with a pavement of crushing teeth, 

 recalling those of many of its Jurassic forerunners. 

 Moreover, in the presence of numerous cycads among its 

 flora, Australia again recalls the Jurassic epoch of Europe ; 

 and it has accordingly been suggested that modern 

 Australia may be regarded as a kind of direct survival 

 from Jurassic times. Before, however, we can say any- 

 thing more as to the affinities of the Stonesfield mammals, 

 we must turn our attention to subsequent discoveries of 

 mammalian remains in other formations. 



The first of these discoveries was made in the year 1847, 

 by Professor Plieninger, of Stuttgart, who obtained certain 

 minute teeth from a bone-bed near that city belonging to 

 the upper part of the Triassic period, which were declared 

 to be mammalian, and for the owner of which the name 

 Microlestes was proposed. Now, as the trias lies below the 

 lias, the existence of mammalian life was by this discovery 

 carried back at one bound very nearly to the commence- 

 ment of the Secondary period. Subsequently, mammalian 

 remains were obtained from the trias of Somerset, which 

 proved to belong to the same genus as those from Stuttgart, 

 while others of a different type were found in the 

 equivalent deposits of North America. 



'FiG. 39. Lower Jaw of an American Jurassic Mammal ; twice 

 natural size. (After Marsh.) 



A little later, the year 1854 was made memorable by the 

 first discovery of mammalian remains in the freshwater 

 Purbeck strata of Dorsetshire, belonging to the very top of 

 the Jurassic system ; from which formation in subsequent 



