Notices of Memoirs.— W. Whitaker—On the Chalk Rock. 427 



the remarkable layer of graphite at Karsok, and probably also the 

 layer of graphite at Niakornet. One has to pass over a tolerably 

 extensive subjacent band of gneiss before arriving at the sedimentary 

 strata, which appear, with a steep inclination, on the bank of the 

 Karsok river at a height of 840 feet. Afterwards, slopes of basalt, 

 boulders, gravel washed down from the mountains, etc., continue, 

 till, at a height of 1150 feet, one arrives at a terrace covered with 

 gravel, in which a few angular fragments of graphite may be dis- 

 covered, as also angular fragments of a hard sandstone impregnated 

 with coal. In consequence of the unfitness of our Greenland as- 

 sistants for real labour, our attempts to dig through the strata of 

 gravel, and reach the graphite bed, were unsuccessful ; but we were 

 informed by Capt. G. N. Brockdorff— master of the ship which, in 

 1850, was to have taken out a cargo of graphite to Europe, and 

 which actually carried over about five tons of that mineral — that the 

 graphite here forms a horizontal bed eight to ten inches thick, 

 covered with clay, sand, and angular fragments of sandstone. This 

 interesting graphite bed does not contain any organic remains ; but 

 as both the underlying Cretaceous strata and those of graphite lie 

 horizontally and in the neighbourhood of each other, and the latter is 

 situated about 300 feet higher up, it is evident that the graphite at 

 Karsok, belongs either to the Cretaceous or to a still later period. 



{To he continued in our next.) 



JsroTTCiHis oip nvnEnvcoii^s. 



I. — On the Occurrence of the "Chalk Eock" near Salisbury. 

 By William Whitaker, B.A. (Lond.), F.G.S., of the Geological 

 Survey of England. 



[From the Magazine of the "Wiltshire Archseological and Natural History- 

 Society, vol. xiii., 1871, p. 92.] 



IN 1861 a bed was described, under the name "Chalk-rock," 

 which, in the counties of Wilts, Berks, Bucks, Oxon, and Herts, 

 seemed to form the top of the Lower Chalk.^ Its occurrence in the 

 Isle of Wight, though in a less marked form, has since been noticed;^ 

 some new sections in North Wilts have been described in the Wilt- 

 shire Society's Magazine by my friend Mr. T. Codrington,^ and I 

 have also seen it in Bedfordshire* and Dorsetshire. As it is open to 

 view near the town (Wilton) where the Society is to hold its meet- 

 ing this year (1870), a description of two sections in that neigh- 

 bourhood may perhaps be acceptable. ■ 



The Chalk-rock, where best developed (from near Marlborough to 

 near Henley-on-Thames), is a hard somewhat crystalline cream- 



^ Quart. Journ. Geol. Soc, vol. xvii., p. 166. See also Geological Survey Memoirs 

 on Sheet 13, p. 19 (1861), and on Sheet 7, p. 5 (1864). 



2 Quart. Journ. Geol. Soc, vol. xxi., p. 400. ^ YqI. ix., p. 167. 



* Mr. J. Saunders, whose notice I called to this bed, has described a section near 

 Luton, Geol. Mag., Vol. IV., p. 154. 



