P. G. Sanford—Analysis of Kentish Rag Stone. 73 
examination of these specimens will demonstrate the wide distri- 
bution of soda-felsites in these districts. Felsites bearing a strong 
resemblance in age, association and mode of occurrence, to the 
Irish rocks occur in Wales. We may confidently expect to find 
keratophyres among them; indeed, Prof. Rosenbusch has already 
predicted their occurrence among the Welsh rocks.’ They appear 
also to occur in Arran. An analysis of a felsite from this island by 
Mr. J. A. Phillips is almost identical as regards the alkalies with the 
one given above.’ 
It is interesting to correlate with the facts given above Prof. 
Haughton’s researches on the Wicklow granites.? As far back as 
1859 he showed that in many of these granites there is a dominant 
soda-felspar; and for these he introduced the name “ soda-granite.” 
An interesting relation has thus been established between the 
granites and felsites of Co. Wicklow. What bearing this has upon 
their mode of origin remains still to be seen. 
VI.—Aw Anatysis oF THE KuntisH Rae. 
By P. Geratp Sanrorp, F.1.C., F.C.S., 
Metallurgical Laboratory, Royal School of Mines, London. 
N May last I visited the Preston Hill Quarry, near Maidstone, 
tin the company of the “ Geological Field Class,” conducted by 
Professor Seeley, F.R.S., and took from it the specimen, the analysis 
of which is given below. In appearance the rock was a hard, grey, 
sandstone, containing fine quartz grains disseminated throughout its 
mass; its sp. gr. = 2°685; on the addition of an acid sulphuretted 
hydrogen was evolved, from the decomposition of calcium sulphide. 
The sample contained :— 
Insoluble Residue ... ... 72°190 per cent = fea ins ALOu= a lo 
Alumina eee eae ents oo lL ammes =9-068 
Ferric Oxide ... doo”) WAI gg = 72°188 
Phosphorie acid, P,03. coo OOS gn 
Lime, CaO. ... soo A os 
Magnesia, MgO. ... ... 0°054 ,, 
Alkalies as K.0. aaeih seu OL 22am, 
Carbonic acid ... sen 9984s. 
Sulphuric acid, S05. ... 0°647  ,, asinsoluble Ca SOx, no soluble sul- 
Calcium sulphide, CaSieeee Milessai [ phates. 
Moisture, at 100°C. ... ... 0°995 ,, 
99-917 
1 Die Massigen Gesteine, Stuttgart, 1887, p. 418. 
2 This MAGazinE, Vol, IX. 1872, p- 540. I give the analysis for comparison :— 
Siog = 78°32 
Al2O3 = 11°39 
FeO = Oz 
CaO SAHIN Sides. ct AOR Re mmmEME bE 13 
MgO (a trace SHGRO SAS). ' oceeh pee Rcmrieal ecr _ 
K, 0 ee 6 seen abo. 20 
Na,0 =) G2 
H.0 — 1°47 
100°80 
8 Trans, Roy. Irish Acad. vol. xxiv. (1859), p. 608. 
