Brief Notices. 427 



Information gathered on the spot by Mr. C. L. Carbutt indicates 

 that the water, which is slightly below boiling-point, is emitted 

 continuously. Mr. J. A. H. Armstrong contributes an account of 

 certain rocks of Archaean age in Natal; they include gneiss, granite, 

 and quartz-diorite. 



8. Denudation and Corrosion. — Professor J.W. Gregory discusses the 

 application of certain terms the use of which has become ambiguous 

 (Geograph. Joum., February, 1911). He suggests that Denudation be 

 used for the wearing down of the land by any agency ; Erosion for 

 the lowering of the land by various subaerial agencies, including 

 rivers and glaciers acting laterally ; Abrasion for the destruction by 

 sea ; and Corrosion for the excavation by rivers and glaciers of their 

 beds. He rightly dismisses Corrasion as a synonym of Corrosion. 



9. The Glenboig Fireclay. — This fireclay, which is obtained from 

 the Millstone Grit Series near Coatbridge, Lanarkshire, and is said to 

 yield fire-bricks of unequalled quality, has been studied by Professor 

 J. "W. Gregory (Proc. Roy. Soc. Edin., vol. xxx, pt. iv, 1910). He finds 

 that its clay-substance is an amorphous hydrous bisilicate of alumina, 

 and may be regarded as the mineral halloysite ; that the fireclay was 

 a lagoon deposit, and that it contains zonal, lenticular, and rhombo- 

 hedral crystals of sideroplesite, which formed in the water and on the 

 floor of the lagoon. 



10. Flint Implements oe North Cornwall. — Mr. H. Dewey (Trans. 

 Roy. Geol. Soc. Cornwall, vol. xiii, pt. vii, 1911) describes and figures 

 some well-formed flint-flakes from the district of St. Clether and 

 St. Tudy. The productive localities are situated on high land, often 

 near ancient encampments, and their local abundance in St. Clether is 

 suggestive of a manufactory of implements. It is considered unlikely 

 that the material was obtained from any of the ancient or modern 

 beaches, but that it was probably brought from the gravels of Haldon 

 in Devonshire. 



1 1 . Arthur's Seat Yolcano. — A description of this ancient volcano, 

 by Dr. E. N. Peach, has been reprinted, with slight alterations, from 

 the memoir on the Geology of the Neighbourhood of Edinburgh 

 (noticed in Geol. Mag., March, 1911, p. 133), and has been issued 

 by the Geological Survey, 1911, price 6d. It is accompanied by 

 a coloured geological map on the scale of 6 inches to a mile, and 

 by four text illustrations. 



12. Miocene Mammals from Nebraska. — In the Annals of the 

 Carnegie Museum (vol. vii, No. 2, 1911) Mr. 0. A. Peterson describes 

 (1) a mounted skeleton of Stenomylus Hitchcocki, a small aberrant 

 camel, the first remains of which were discovered a few years ago. 

 There have since been found in the Lower Harrison Beds more 

 complete remains of this genus than of any other Miocene mammal. 

 They were obtained by Dr. F. B. Loomis in a hill of closely packed 

 and finely grained sand, about 60 feet thick, overlain by bedded 

 sandstone, in the Niobrara Valley, Sioux County. The excavation 

 is known as the Stenomylus quarry, and a plan is given showing 

 the position of seventeen skeletons and other less complete remains in 

 an area of about 75 by 20 feet. Mr. Peterson also describes (2) a new 

 camel, Oxydactylus longirostris, from the same formation at Whistle 



