Rocks at Ferriters Cove 10

This marks the final post in the series about the rocks at Ferriters Cove. I had spent a happy few hours on the beach and reached the limit of accessible shore at Ferriters Cove. Time to call it a day. At this northernmost part of the shore, the steeply sloping strata in the cliff, with the bedding planes facing outwards as a continuous sheet, at first seem to be buckling under their own weight, as seen in images 55a and 56 in the previous post. Then, just a few metres further on, the strata can be viewed side-on across the bedding planes with the sequence of individual layers revealed. The strata are curved concavely so that the cliff face is like the under-side of a huge wave, the crest of which is curving over and about to crash down and break. You can see this best in images 60 and 61.

There are also some enigmatic markings on that part of the bedrock on the beach which is covered each day by the tide. I wonder if these are fossils. Photo 73 has a number of rounded shapes that look like they might be gastropods; and Bembexia is a marine snail that is recorded in this locality.

More problematic are the plant-like patterns which occur on a number of rocks (see images 79 – 81). They seem to have a central stem with numerous branchlets along the length. I am not at all certain that these are fossils although they seem to be integral with the surface of the rock and to have a slightly different composition which is reflected in the fact that there is no black biofilm (maybe lichen) growing on them. I am fairly sure that the ‘plants’ are not grazing trails left by the feeding activities of the adjacent limpets and periwinkles. Plants are in fact recorded from the Silurian but I cannot find any illustrations that resemble these Ferriters Cove ‘plants’.

In an article about the Silurian Period on the website of the University of California Museum of Paleontology it says:

Perhaps the most striking of all biological events in the Silurian was the evolution of vascular plants, which have been the basis of terrestrial ecology since their appearance. Most Silurian plant fossils have been assigned to the genus Cocksonia, a collection of branching-stemmed plants that produce sporangia at their tips.

However, drawings of that particular genus show a very different branching system to that exhibited by the Ferriters Cove ‘plants’. Maybe I will get a clearer understanding when I have tracked down some of the specialist research papers on the fossils of this area such as those written by C. H. Holland:

Holland, C. H. (1969) Irish counterpart of the Silurian of Newfoundland. Memoir of the association of Petroleum Geologists 12, 298-308.

Holland, C. H. (1987) Stratigraphical and structural relationships of the Dingle Group (Silurian), County Kerry, Ireland. Geological Magazine 124, 33-42.

Holland, C. H. (1988) The fossiliferous Silurian rocks of the Dunquin inlier, Dingle Peninsula, County Kerry, Ireland. Transactions of the Royal Society of Edinburgh: Earth Sciences 79, 347-360.

Rocks at Ferriters Cove 9

Cliff of Silurian strata at Ferriter CoveBy the time I had reached the northernmost edge of the beach at Ferriters Cove, the Silurian rocks had changed their appearance again. The cliff here is higher and composed of a wonderful patchwork of mainly yellow slabs with purple-grey markings. Many of these slabs have fallen to the shore in a thick loose layer. Among these pieces of stone I found some more fossils, internal casts and impressions of brachiopods, including different species to the one I found earlier (I thought that might be Leptaena sp.). Two particular brachiopods are mentioned on the sign at the entrance to the beach, Holcospirifer (bigugosus?) and Rhipidium (hibernicum?), and it is likely that the fossils in images 57b,c,& d belong to one or both of those species. I am wondering if the much larger regular rounded fossil in image 57a is a species of Atrypa.

REFERENCE

Bassett, M. G., Cocks, L. R. M., and Holland C.H. (1976) The affinities of two endemic Silurian brachiopods from the Dingle Peninsula, Ireland, Palaeontology, Vol. 19, Part 4, pp. 615 – 625, pls. 93-95.

Rocks at Ferriters Cove 8

Natural abstract design in Silurian rock at Ferriters Cove

Water-worn, soft, and stripey Silurian sedimentary rocks make sporadic appearances through the sandy beach at Ferriters Cove and sometimes they can have a strangely sculptural appearance, or even of a landscape in miniature, depending on the perspective from which they are photographed. I also particularly like the pale blue-green colour contrasting with the muted yellow that contributes to the natural abstract striped designs.

You can click on an image to enlarge it.

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Silurian rocks on the beach at Ferriters Cove

Rocks at Ferriters Cove 7

Natural pattern, shape, and texture in Silurian bedrock at Ferriters Cove

The last part of the Silurian strata exposure of the small rocky promontory at Ferriters Cove, before the wide sandy strip with beach stones, is very abstract…. but not so sculptural in appearance as the patches of water-worn mudstones that emerge here and there through the sand – see the next post!

Beach Stones at Ferriters Cove

View of Ferriters Cove on the Dingle PeninsulaBetween rocky outcrops and promontories at Ferriters Cove lie stretches of sandy beach with patches of water-worn beach stones and smaller pebbles. The stones are derived from a variety of Silurian strata, not only from this cove but also from the coast further to the north which is also composed of Silurian Period rocks.

Rocks at Ferriters Cove 6

The character of the rock changes as I continue my walk around the shoreline at Ferriters Cove in the Dingle Peninsula. Successive Silurian bedrock strata have different textures, colours, shapes, and sculpturings, each layer having originally been laid down on the bottom of an ancient shallow sea in varying environmental conditions that affected the chemical constituents and particle size of the sediments deposited, and the subsequent disturbance of each new layer.