British Associaton. 289 
aid of a grant from the British Association), by Mr. Henry Hicks. 
His energetic work has already brought to light more than thirty 
species of fossils, most of them 'Trilobites. Some of these are quasi- 
embryonic forms, such as Microdiscus, which, like Agnostus, is a blind 
Trilobite without facial sutures ; but it has four body-rings, instead 
of two. There are also species of Conocoryphe and Agnostus, both 
of them well-known genera, and others allied to Arionellus of Bar- 
rande; all of them have a ‘primordial’ aspect. Among the new 
discoveries is a new genus, named Anopolenus ; a remarkable form, 
which at first seemed to have the head devoid of eyes and of any 
facial suture. Later observations, however, have discerned the cheeks, 
eyes, and head-spines in a most abnormal position,—placed far for- 
ward on the head, and so easily separable as to justify the previous 
belief in their entire absence. In order to find a parallel for this 
bizarre form, the author was obliged to describe a new Olenus, or 
rather Spherophthalmus, found by Mr. Turner, of Pauntley, in the 
Black Shales of Malvern. In this fossil the characters so much 
exaggerated in Anopolenus are less strongly pronounced; and the 
new genus is thus connected with the older and better known forms 
of the Olenide (the most ancient Trilobite family, if we except 
Agnostus and its allies, which were probably coeval with them). It 
is worthy of remark, that in this earliest family ( Olenide) the largest 
size attained by the group of Trilobites is reached; the great 
Paradoxides Harlani being nearly 22 inches long. 
In reply to a question put by Mr. Pengelly, Mr. Salter stated that 
the exceptional blind species found in the latest formations known to 
contain Trilobites are degraded forms of the highest groups, namely, 
Phacops and Phillipsia, and that there is good evidence of a progres- 
sion in the development of the group from its commencement in the 
Cambrian to its extinction in the Coal-period. 
A Pru-Camprian Istanp, at St. Davip’s, Pemproxssutre. By J. W. Sarrer, 
Esq., A.L.S., F.G.S8. 
) BS been occupied for a fortnight this summer in searching 
(with Mr. H. Hicks) the Cambrian rocks of St. David’s for 
the Olenoid Trilobites mentioned in the last paper, the author paid 
some attention to the relations of the central trap-rock of the district, 
which runs in a broad mass, a mile or two wide, from Llanreithan to 
the headland of St. David’s, and is continued out to sea in Ramsey 
Island. As the purple rocks, sandstones, and slates of the whole 
Lower Cambrian division are thrown up at high angles, all but ver- 
tical, on either flank of this mass, which forms the axis of the whole 
country, there is no difficulty in studying its behaviour in contact 
with the Cambrians. If it were an intrusive trap of later date, it 
would penetrate them here and there, or at least alter them at the 
point of contact, as the neighbouring granite of Brawdy and Roch 
actually does. On the contrary, wherever the boundary can be seen, 
steatitic and felspathic schist unaltered, and beds of thick con- 
glomerate, mark the line, and are often very conspicuous. These 
conglomerates—of quartz-rock, jasper, felstone, &c.—may or may 
not have been derived from the immediate neighbourhood. They 
