250 E. E. Eoicorth— The Mammoth and the Glacial Drift. 



Somerset/ supplemented by tlie present communication, will be 

 benefited by the addition of more speculative correlations. 



My friend Dr. Hatch has kindly sent me the following notes on 

 specimens of the New Ked Volcanic rocks of South Devon. 



Notes on Sliced Specimens of the Exeter " Traps," in the Collection of 

 the Geological Survey at Jermyn Street. 



Olivine-basalt or melaphyre, composed of lath-shaped striped 

 felspars and scattered grains of magnetite, with calcite, replacing 

 augite, and ferruginous pseudomorphs after olivine. 



Localities: Raddon Court (No. 951), Pocombe (No. 953), between 

 Chiphele and Budlake (No. 958), and Quarry near Crabtree, Kellerton 

 (No. 945). 



Porphyrite (Andesite) : A felted aggregate of lath-shaped and 

 microlitic striped felspars, with occasional porphyritic crystals of 

 plagioclase. Localities : Western Town, Ide (943), Quarry N.E. of 

 Knowle, N.E. of Holcombe-Burnell (946), and Knowle Quarry, W. 

 of Duncliideock (949). The last two, with rounded (corroded) 

 grains of quartz. 



Mica-porphijrite [Mica- andesite or trachyte). — Finely vesicular 

 rocks containing brown mica, imbedded in a minutely microlitic 

 ground-mass, which is generally rather obscured by the presence of 

 dusty magnetite and secondary calcite. 



Localities: Kellerton Park (Nos. 944, 947 and 950). The nature 

 of the felspar in these rocks is indeterminable, but specimens from 

 Copplestone (Nos. 957 and 959) consist of a holocrystalline aggre- 

 gate of broad lath-shaped crystals of orthoclase, flakes of brown 

 mica and magnetite. 



III. — Did the Mammoth Live Befoke, During, or After the 

 Deposition of the Drift. 



By Henry H. Howorth, M.P., F.G.S., etc. 



IN recent papers which I have printed in the Geological 

 Magazine I have tried to show that some of the greatest 

 mountain chains in the world are of very recent origin ; and tliat 

 this accounts for their showing no traces, or very slight ones, of the 

 action of ice on a wide-spread scale. 



I have, in fact, ventured to lay down the conclusion that the 

 presence or absence of such traces of ice-action is a test of whether 

 these mountains existed at the so-called Glacial period or not. 



If my view be right, it follows that very large masses of land 

 were thrown up suddenly or very rapidlj' in post-Pliocene times ; 

 and, if this was so, it is veiy probable that there was a great sub- 

 sidence of land in other parts corresponding to this upheaval. I 

 believe that this can be proved, and that it involves some important 



^ Geol. Mag. for April, 1875; Quart. Journ. Geol. Soc. Aug. 1864 ; February, 

 1870; Nov. 1876; Aug. 1878; Trausactions of Devonshire Association, 1877, 

 1878, 1881 ; and the Proceedings of the Somersetshire Archseological aud Natural 

 History Society for 1889, vol. xxxv. 



