¥ 
Mr. Farey’s Notes on Mr. Bakewell’s Geology. 253 
[P.252] cle is now manufactured on Earl Mulgrave’s Estate, from 
’ stone which was discovered to have these properties, by his 
Lordship’s architect, Mr. William Atkinson, Rep. ii. p. 6. 
Notwithstanding this, a very learned Wernerian periodical 
Writer, lately told one of his correspondents, who inquired the 
composition of this Cement—“ If I recollect right, it is com- 
posed of clay, iron-stone, and lime, beaten together;’’—in- 
_ stead of telling him, that the ‘ clay-balls” are merely calcine 
to expel the water, and then pounded and ground to a fine 
powder, without any admixture, as is now so well known, and 
as the specification of Parker’s patent, stated many years ago. 
255, Plate IV. See pages 11 and 256 in Mr. B’s volume. 
255, 1. 11, were it attainable*.—* Mr. William Smith long 
ago attained vastly greater ‘ accuracy of detail”’-in his Geo- 
logical Maps, as to nearly all the most important parts of 
England and Wales, P. M. xxxix. p. 425; Mr. Cary, in 
the Strand, has assured me that his Maps will soon be pub- 
lished, as mentioned in my Ist Letter, xl. p. 42. Since these 
Notes were principally written, I have observed, P. M. xlii. 
p- 125, that Mr. B. acknowledges his theoretic “classes and 
orders,” only, to be within his power to delineate on Geo- 
logical Maps, and that * mifute accuracy of detail,’ “ can 
only be applied to small districts or estates. !” 
256, 1. 22, alpine district * —* This is extended from Devon- 
shire much too far northward; and so in a less degree on 
.the NW of Chester, and in Anglesea, see my Ist Letter, vol. 
xlii. p. 57. ‘ 
257, 1. 6, low district *.—* The extension of this is wanting 
in the Map, Plate IV. at its‘northern end and SW corner, 
as is pointed out in my Ist Letter. The former of these 
errors seems needlessly charged on Mr. Tuke, in page 206. 
1. 10, middle district +.—+ The extension of this is too 
great on the N of York, and W of Scarborough, and around 
and to the E of Exeter, and too little on the W and SW ot — 
Bath, &c.see my Ist Letter, xlii. p. 97. 
258, 1. 12, upper part of this Clay *.—* The alluvium on it, 
see my Note on p. 16, and 181. 
1. 18, on the very spot ¢.—+ ‘Phe importance of the fact 
here related, (though with considerable obscurity) of an ele- 
phant’s tusk being found zm the upper part of the London 
Clay, has occasioned me to make several inquiries of persons 
resident in and near Shoe-Laue: and the results of these in- 
quiries have been, that ‘ the very spot’’ alluded to by Mr. B. 
4 Since the above was written, I have observed, that a correspondent of 
Dr. Thomson’s in his Ann. of Phil. ii. 148, secms almust to have persuaded 
him, that “transitiva limestone,” occurs at Filley, SE of. Scarborough, see 
P. M1. alii. p, 94. was 
