508 Notices of Memoirs—H. Fox—On Radiolaria. 
X.—On THE RapionariAN Cuerts or Cornwatt. By Howarp 
Fox, F.G.S. 
HE Mullion Island Radiolarian cherts were first recognized by 
Mr. J. J. H. Teall, F.R.S., in rocks sent to him by the author 
last autumn, and a joint paper was read at the Geological Society’s 
meeting, February 8 last, describing the manner in which they 
occur. Dr. Hinde accompanied the paper with a description of the 
species recognized and with micro-photographs of the individual 
organisms. 
Last Easter Mr. Teall, Professor Lapworth, and the author traced 
these cherts for about 650 yards in the cliffs and on the foreshore 
from the south end of Nelly’s Cove, near Porthallow, Meneage, to 
near Ligarath Point, south of the Nore Point. Subsequently the 
author has examined the coast and some inland districts between 
Helford River and Fowey, and has found other exposures in the 
following places :— 
Pendoner Beach, Veryan (for about 1000 yards).—Beds many feet 
thick at the west end of this beach, on which the raised beach rests. 
Angular fragments of chert are enclosed in the raised beach, and in 
one place a mass of chert and slate cliff has been thrust over it, and 
thus the chert appears both above and below as well as in the raised 
beach. Towards the eastern end of this beach the chert beds become 
thicker and more numerous. 
Portloe Point, Veryan.—Here several beds, varying from one to 
six inches in thickness, are seen for 20 yards in the volcanic breccia 
(or ‘‘trappean conglomerate” of De la Beche) associated with some 
small amount of shale and grit, more or less decomposing from the 
presence of iron. Two small exposures are traced inland, one of 
which is 500 yards west of Portloe Point. 
Pecunnen Cove, Gorran.—North-west of the Dodman beds of chert 
are seen in perpendicular thinly laminated crushed-dark slates for 
60 yards, accompanied by numerous lenticules and bands of black 
quartzite and yellowish-grey limestone. 
Inland exposures are traced at intervals in a line extending for 
five miles inland from Pendoner Beach in a north-east direction 
through the village of Veryan to Tolcarne Mill, north of St. Michael 
Caerhays. These cherts on the mainland are less pure than those 
in Mullion Island, and the structure of the individual organism is 
destroyed. Some specimens show signs of great shearing and 
crushing, and have no traces of Radiolaria; others show shearing 
with slight traces of Radiolaria, whilst others show no signs of 
crushing, and have clear round spaces, evidently due to Radiolaria. 
In many of the specimens examined a considerable amount of ferric 
oxide has been formed by the decomposition and oxidation of pyrites, 
and possibly also of ferriferous carbonate. At Portloe Point the 
chert appears to pass into quartz. 
The Meneage and Veryan cherts are associatéd with the well- 
known Ordovician quartzites of those districts, and appear to le 
immediately under them; but the sequence is not absolutely clear, 
and no typical fossils have yet been found in the shales and slates 
with which the cherts are interbanded. 
