x 
7 ‘ 
Péer Ill. Sxor.ii§2] JURASSIC. — 783 
yielded the remains of four genera—Amphilestes and Phascolotheriwm 
(Fig. 381), probably insectivorous, the latter being related to the 
living American opossums; Amphatherrwm, resembling most closely 
the Australian Myrmecobius ; and Stereognathus, which Owen is dis- 
posed to think was rather a placental, hooted, and herbivorous form. 
Higher up in the English Jurassic series another interesting group 
of mammalian remains has been obtained from the Purbeck beds, 
whence upwards of twenty species have been exhumed belonging to 
eleven genera (Spalacotherium, Amblotheriwm, Peralestes, Achyrodon, 
Peraspalax, Peramwus, Stylodon, Bolodon, Triconodon, Triacanthodon), 
of which some appear to have been insectivorous, with their closest 

Fide. 380.—Birp (ARCHMOPTERIX MACRURA) (Owen)—SoLENHOFEN LIMESTONE 
(Middle Jurassic). 
a, Tail and tail-feathers (4); b, Caudal vertebrae (nat. size); c, foot (4). 
living representatives among the Australian phalangers and American 
opossums, while one, Plagiaulax, resembling the Australian kangaroo 
rats (Hypsiprymnus), is held by Owen to have been a carnivorous 
form.! 3 
§ 2. Local Development. 
The Jurassic system covers a vast area in Europe. Beginning at the 
west, remnants of it occur in the far north-west of Scotland. It ranges 
across England as a broad band from the coasts of Yorkshire to those of 
Dorset. Crossing the Channel it encircles with a great ring the Creta- 
ceous and Tertiary basin of the north of France, whence it ranges on the 
one side southwards down the valleys of the Saone and Rhone, and on 
1 See Falconer, Q. J. Geol. Soc. xiii. 261; xviii. 348; Owen, Monograph of Mes. 
Mammals: Palzontograph. Soc. 1871. 
. 
