88. ON THE OCCURRENCE OF CHALK 
Mr. David Forbes, F.R.S., also examined some specimens of 
chalk, the analyses of which are here cited. The first analysis 
shows the composition of a piece of white chalk from Shoreham, 
ah al and the second of a piece of grey chalk from Folke- 
White Chalk. Grey Chalk, 
Calcium carbonate ah ... 98°40 94-09 
gnesium carbonate ... re ‘0S “31 
Phosphorie aci : 
Alumina and loss “ite 42 trace 
Sodium chloride ... ed ree —_ 1:29 
Water... ie: c =e — -70 
Insoluble rock debris... oo) BGS =i 3°61 
100°00° 100-00 
(Vide “ Geology of England and Wales.” Woodward, p. 239.) 
Another sample of chalk obtained from a well at Driffield was 
found by Mr. 'T. Hodgson to have the ene composition : ge 
Calcium carbonate... nae ... 93:30 
agnesium carbonate Hi ees 15 « 
Iron ee and alumina i 20 
Silica a was sie ig RR 
100-00 
The specimen from New Ireland closely resembles in chemical 
composition the chalk-like rock occurring in New Zealan 
r. Hector, C.M.G., F.R.S., Director of the Geological Survey 
of ave Zealand, publishes i in his aries Report for 1875-6, the 
description and analysis of a limestone made by Mr. Skey, 
chemist to the Survey, as follows se No. 1,767. Chalk, con- 
tributed by Mr. H. Hispiascs. from South Canterbury, very 
closely resembles some taken from the same distritt by the 
Survey some time since. Thesg samples, as to their physeet and 
chemical nt their general appearance, exactly repre- 
ecurrin in 
sent the ¢ he cretaceous formation as oce 
land,” 
ae 
Carbonate of lime __.. ae .. 9412 
Carbonate of magnesia ite oe eee 
y aia oi See 
Iron oxides and. alumina, soluble inacid 121 
~ 100°00 
RS ee 2 oe eet ne te RES ae 
