392 Baily— Cambrian Rocks and Fossils. 
an assemblage of fan-shaped rays, arranged in alternating series, is 
shown at fig. 4, p. 394. 
The first published account of these fossils was given by 
Dr. Thomas Oldham, then Curator of the Geological Society of 
Dublin, and Professor of Geology in Trinity College (now Super- 
intendent of the Geological Survey of India), who, with the keen 
discernment of a naturalist, saw in them something more than mere 
markings ; and, in a paper read before the Geological Society of 
Dublin, ‘On the Rocks at Bray Head,’ * observed, ‘that he had not 
as yet been successful in finding organic remains in the slate-rocks. 
of Bray Head, with the exception of some small zoophytic markings, 
which did not appear referable to known genera.’ Some years after- 
wards, that eminently gifted naturalist, the late Professor Edward 
Forbes, when Palzontologist to the Geological Survey, threw still fur- 
ther light upon them by a communication made to the same Society, 
entitled ‘On Oldhamia, a new genus of Silurian Fossils. + After 
alluding to the rarity of organic remains in the Cambrian or oldest 
portion of the Silurian strata, he says, ‘The earliest fossils which 
have yet been discovered seem to be certain plant-like impressions 
or casts discovered by Professor Oldham at Bray Head, in Wicklow, 
and referred to by him in his communication to this Society in 1844. 
These bodies present the appearance, in most specimens, of a central 
filiform axis, with fasciculi of short radiating branches proceeding 
from its sides at regular intervals, or of bundles of such filiform rays 
without an axis. A close examination of them shows that each 
branch is formed of a series of articulations marking the positions of 
minute cells. The entire body presents a striking resemblance to 
the arrangement of parts in certain Zoophytes, as in Sertularia 
cupressina, but are also consistent with those exhibited in many 
Bryozoa, as in Gemellaria and Cellaria, an alliance more in accord- 
ance with the minute structure.’ He also observes, ‘I propose the 
name Oldhamia for these remarkable fossils, in honour of their 
discoverer, who has in them made us acquainted with what in all 
probability is a group of Ascidian Zoophytes, or rather, compound 
Tunicated Molluscs, in stratified rocks of very early date, and has 
thus furnished an additional and important fact in contradiction 
of the crude notion that the earliest forms of animals are the most 
rudimentary.’ 
No further details respecting these fossils were published, or 
figures of any consequence given, until the late Dr. J. R. Kinahan, 
a young naturalist of great ability, directed his attention to the 
investigation of rocks ascribed to the Cambrian formation in Ireland; 
his perseverance and zeal being rewarded by the discovery of the 
Oldhamia in the cliffs of Howth, county of Dublin, and the record- 
ing of several additional stations for it in those of Bray Head and 
Greystones, county of Wicklow, where he collected more distinct 
and perfect specimens, and obtained some other forms of animal 
* Journ. Geol. Soc. of Dublin, vol. iii. p. 60 (1844). 
t Zbid., vol. iv. p. 20 (1848), 
