68 REPORT—1868. 
On some recent Discoveries of Fossils in the Cambrian Rocks. 
By Henry Hions, M.R.CS.E. 
In the “ Report on the Menevian Group and the other Formations at St. David's” 
to the British Association in 1866, by Mr. Salter and the author, it was stated that 
no fossils had at that time been discovered by them during their researches in the 
neighbourhood, below the topmost purple beds of the Cambrian rocks, or rather 
in that series consisting of purple, red, and green sandstones, shales, and conglo- 
merates, well known to halone to the “Harlech group” of Prof. Sedgwick, and 
“Upper Longmynds ” of Sir R. Murchison. 
In the summer of last year,however, the author was fortunate enough to find a small 
Lingulelia in one of the red beds at the upper part of the series, and soon after- 
wards the same species in beds much lower, along with indications of other fossils. 
During the present summer, again, the author has been able to go still deeper, and 
to prove beyond doubt the presence in the series of a really rich fauna, com- 
prising species belonging to no less than ten different generu (in addition to the 
tracts and burrows of Annelids), and consisting of Trilobites, Phyllopods, Brachio- 
pods, and Pteropods. Therefore that portion of the Cambrian rocits known 
as the “ Harlech group” or ‘“ Upper Longmynds,” cannot henceforth (and as it 
has hitherto been) be classed with the so-called sterile bases of the fossiliferous 
rocks, but rather looked upon as a highly important group, which contained the 
imperishable monuments of almost the earliest states of life known. These dis- 
coveries also seem to lead the mind at once to anticipate the more than probable 
fact, that wherever sedimentary rocks occur, evidence of former life, in some shape, 
is likely to be present, and also to be disclosed ere long. 
The section exhibited was taken across the line of strike of the Cambrian beds, 
on the coast to the south of St. Dayid’s, extending from the central mass of 
altered beds (syenite of the Survey map) to the base of the “ Menevian group,” 
and including oyer 1500 feet of nearly vertical strata, comprising in ascending order, 
1, Conglomerates .......... 50) 
2, Olive-green sandstones .... 250 | 
3, Red and purple sandstones. 850 | 
Fossiliferous {a Yellowish and greenish sand- 
series, ) BLONICS., apofe.celerisBy< pins aiele 300 ( 
5. Purple and red sandstones. . 100 
A few grey beds at the base 
of the “ Menevian Group.” 
Lower Cambrian. 
Over 1200 feet of the section are now known to contain fossils, and to haye be- 
longed to a period when the Crustacea, Brachiopoda, and the Annelida were in 
existence; the lowest fossils found, next to the Annelid markings and tubes, 
being Lingulella and a small bivalved crustacean nearly allied to Leperditia. The 
valves of the latter are found as small ovate, convex plates. The author's friend Mr, 
Salter, to whom he sent some specimens, states that the “ regular convexity and mar- 
ginate outline show them to be nearly perfect valves. The oblique, parallel, but 
inosculating plication agrees with crustacean ornament, and no other; and the eyi- 
dently thin shell (with no lines of growth) suggests a carapace of a crustacean, 
and not the shell of a Brachiopod, which is the only obvious alternative.” These 
occur, along with Lingulella ferruginea, in some rather fine-grained red beds inter- 
vening between the olive-green grits, almost at the base of the section, and the 
purple sandstones above. They are also tolerably plentiful: but the colour of the 
rock is rather unfavourable to the exhibition of their minute characters. In the 
succeeding thick and compact beds of purple sandstones scarcely any traces of 
fossils have been found, nor indeed until about 50 feet of the yellowish sand- 
stones of the overlying series have been passed. We then, however, meet with a 
bed exceedingly rich in fossils, equalling, indeed, in richness any of the beds of the 
“‘Menevian group;” but nearly the whole of those above and below seem almost 
altogether barren ; and the author cannot help thinking that this strange barren- 
ness in Close proximity to a yery rich colony, along with the fact that such colonies 
