1822.] imbedded in Calcareous Rock. 337 
solved a considerable portion ofit, a fine siliceous powder fallin 
during the process. The undestroyed portion of the shel 
remained as a thin irregularly shaped mass of chalcedony. On 
this of course acids had no further effect. The specimen, there- 
fore, exhibits a singular instance of a shell preserved partly in 
siliceous and partly in calcareous matter. 
These are the only cases of this phenomenon which I have 
hitherto had the opportunity of examining. 
Believe me, my dear Sir, very truly yours, 
J.J. CONYBEARE. 
ArtTIcueE III. 
On the Geology of the Malvern Hills. 
By the Rev. J. J. Conybeare. 
(To the Editor of the Annals of Philosophy.) 
MY DEAR SIR, Bath Easton, Oct. 4, 1822. 
A suortT residence at Malvern in the summer of 1821 enabled 
me to verify most of the statements contained in your brother’s 
very accurate survey ofits neighbourhood, and to observe some 
few circumstances, the detail of which (as they are unnoticed 
or not viewed in the same light, either by that gentleman, or by 
Mr. L. Horner), may, perhaps, be regarded as contnbuting 
somewhat more towards the history of that interesting tract. 
I would first notice the character of the two remarkable con- 
glomerates connected with the syenitic rock.* The first of these 
occurs in blocks (which I was unable to trace to their original 
site) a little southward of the road leading to the Wych. (The 
wall in particular which supports the ground in front of the cot- 
tage, named North Lodge, contained many specimens of it.) 
lt is composed of amorphous nodules of the small-grained red 
syenite, abounding in felspar, imbedded in a paste, so precisely 
resembling the nodules themselves, as to preclude all supposition 
of its being a mechanical mixture. A recomposed granitic rock 
(as it has been termed) possessing nearly the same characters, 
was found by my friend Dr. Daubeny in loose blocks near Ard- 
namuchan, N.B. M. Bout (Geologie de l’Ecosse, p. 22), men- 
tions a rock of the same nature as occurring near the Fall of 
Fyers. (See also Dr. Macculloch’s Classification, p. 580, G. 6.) 
Another conglomerate, evidently belonging to the same class, 
was found 7m situ on the road leading from Casile Morton Com- 
™ These are, if I mistake not, the last rocks mentioned in Mr. W. Phillips’s Cata- 
logue. ‘The former is probably that described by Mr. L. Horner, T, G, 5, yol. i. 
p. 295. § 26. 
you. tv. (New Series.) 7, 
