340 Mr, Richard Phillips on some [Nov. 
pance between me and that gentleman will be found to be very 
inconsiderable, especially when it is recollected that six years 
have elapsed since my short tract was written. With their own 
hypothesis in view, your correspondents assert that I describe 
the oolite formation as immediately succeeding or being in the 
vicinity of the northern Cleaveland Hills, but my line of demar- 
cation, already referred to, will serve to show the fallacy of this 
statement; and Robin Hood’s Bay not being more than between 
six and seven miles from the oolite hills, I still think these may 
be seen when three miles south of that place. Another of their 
leading remarks is, that I associate Danby Beacon with the 
mountains of the northern part of the district, ‘“‘ whereas it is 
one of the most southern.” The truth is, that the hill in ques- 
tion is 26 miles distant from the southern, and eight from the 
northern termination of the lias formation at the foot of Rose- 
bury. 
The minor objections may be dismissed in a few words. 
Felay Head is in the oolite district (see Greenough’s map). All 
the shale beds ofthe lias formation contain nodules called ironstone 
balls, consisting of carbonate of lime, clay, and peroxide of iron. 
That the hard shell limestone of the vale of Pickering is distinct 
from the Thirkleby limestone, [ am now convinced by the evi- 
dence of Prof. Buckland in his paper on the Kirkdale cave, the 
former being a bed in the oolite, and the latter a bed in the lias 
formations, Iam, Sir, your obedient servant, 
N. J. Wincn. 
ARTICLE V, 
On some peculiar Crystals of Sulphate of Potash. 
By Richard Phillips, FRS. L. & E. &c. 
Tue crystals which I am about to describe were presented to 
me by Mr. Hills, of Bromley, patentee of the advantageous mode 
of preparing sulphuric acid from sulphuret of iron; they were 
formed by slow crystallization in a large quantity of the solution 
of the residuum, after preparing nitric acid from sulphuric acid 
and unrefined nitre. 
From such a source, it would be expected that crystals of 
sulphate of potash only would be procured, but as the form of 
the crystals in question is totally different from that which sul- 
hate of potash usually presents, it appeared to me possible 
either that they might contain water of crystallization, or excess 
of acid, that they might contain chlorine, or consist of a double 
salt with an alkali and earthy base; or, lastly, that the crystals 
