74 General Notes. [January, 



lower jaw, which I discovered in 1872, were nearly erect as in 

 man and the Simiidce, and not procumbent as in most Lemurs. 

 The cerebral hemispheres are remarkably large for an Eocene 

 mammal, extending to between the middles of the orbits; the 

 anterior parts, at least, are smooth. The cerebellum piojected 

 beyond the foramen magnum posteriorly, as in Tarsius. The or- 

 bits are large, approaching those of Tarsius, but are not so much 

 walled in by a septum from the temporal fossa as in that genus. 

 The superior molars have only one internal cusp. 



The species, which I propose to call Anaptomorphus homuncu- 

 Ins, has a wide palate much as in man, and the true molar teeth 

 diminish in size posteriorly. The pterygoid and zygomatic fossae 

 are short and wide, and the petrous bone is large and inflated. 

 The animal was nocturnal in its habits and was the size of a mar- 

 moset. The genus is nearer the hypothetical lemuroid ancestor 

 of man than any yet discovered. — E. D. Cope. 



The Arch^an Rocks of Great Britain.— Professor Hull, 

 director of the Geological Survey of Ireland, discriminates two 

 petrographic types in the British Cambrian beds, the one consist- 

 ing of purple sandstones or conglomerates, the other of hard green 

 and purple grits and slates. The former is the " Caledonian " 

 type, and is found in the north-west Highlands of Scotland. The 

 second is the Hiberno-Cambrian, and characterizes East Ireland 

 and North Wales. Professor Hull thinks these formations were 

 deposited in distinct basins, which were separated by an Archaean 

 ridge of crystalline rock which extended from Scandinavia, 

 through the central Highlands of Scotland to Northwest Ireland. 

 The Caledonian basin was an inland lake, the crystalline rocks 

 of the outer Hebrides forming its western shore. Professor Hull 

 also finds the Laurentian granite in N. W. Ireland overlaid un- 

 conformably by the Lower Silurian quartzite schists and lime- 

 stones. — Geological Magazine. 



A New British FoRMATiON.^-The name Devono-Silurian is 

 given by Professor E. Hull to a series of cotemporary deposits 

 found in various parts of the British Isles, and to some extent on 

 the continent. He finds them in Devonshire and on the Welsh 

 borders, and probably concealed in Southeast England ; also, in 

 the south of Scotland and North and South Ireland. The beds 

 were deposited under estuary or lacustrine conditions, and con- 

 stitute a great group between the Silurian on the one hand, and 

 the Devonian on the other. — Geological Magazine. 



Recent Extinction of the Mastodon.— The existence of the 

 mastodon in North America must have been more recent than 

 commonly supposed. A number of new facts bearing on this 

 subject are to be found in Professor John Collett's "Geological 

 Report of Indiana for 1880," recently issued. Of the thirty indi- 

 vidual specimens of the remains of the mastodon (Mastodon gi- 

 ganteus) found in Indiana, in almost every case a very considera- 



