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The area around the Moray Firth in North Eastern Scotland has historically given us much Devonian Fish material, leading to insights into the Southern Margin of the Great Orcadian Basin.
The fish bed at Tynet Burn was first discovered in 1838 and specimens were sent to Luis Agassiz (a pioneering Swiss Palaeontologist) these featured in his research papers of the 1840's. This site and others were brought to the attention of the Victorian public by the collector Hugh Miller (1841), a former stonemason and talented writer of the time. The fossils from Tynet Burn were reviewed more thoroughly by Ramsey Traquair (1895). Peacock et al (1968) described a section near Tynet Mill and identified a Lower and Upper Nodule Bed.
The Lower Nodule Bed has yielded only fish fragments notably Coccosteus the bed, exposed on the east bank of the burn is not exceptional at fish fragments occur infrequently throughout the sequence.
The Upper Nodule Bed, high on the river cliffs has been worked out at outcrop, in the past yielding large quantities of beautifully preserved fish. These were found in carbonate nodules, which tended to be fish shaped. These nodules suggest that sediments were deposited in shallows water; they are absent further north at sites in Caithness and Orkney which are thought to represent more alkaline, deeper water environments. There are conflicting reports of how many fish beds are present in this unit- from one to three.
In 1989/90 Stan Wood undertook three excavations to clarify and extend work that had been done there in the past. Two trial excavations were to pinpoint the extent of previous quarrying activities on the north bank and to locate the fish bed horizon from the 19th century workings at the western end of the site, now providing a permanent outcrop of this horizon.
The third excavation on the north bank and to the west of the older quarrying was to provide more material and answers about the environment of deposition.
Stan Wood's work divided the geology into 3 units termed Lower, Middle and Upper and has shown the lateral incontinuity of fish bearing horizons, thus leading to the discrepancies in number of fish beds reported.
The Lower unit, in deeper depressions consists of shale with fish scales. This is succeeded by a banded pink shale with fish-shaped nodules giving a fauna dominated by crossopterygians (Osteolepis and similar lobe-finned forms).
The Middle unit is a more widely distributed limestone with a more varied fauna.
The Upper unit, again a pink banded shale with nodules, is more widely distributed and unrelated to depressions. Fish are contained in deep oval nodules with a predominance of acanthodians (Cheiracanthus and similar 'spiny sharks').
13 species in total were found during these excavations,
including one new to science, and the work done in opening up
a new permanent outcrop will eventually allow correlation between
the 19th century collections and the units which they
came from.
Samples of the new material are to be found at:
The Natural History Museum, London
The Royal Museum of Scotland, Edinburgh
Hunterian Museum, Glasgow
Ulster Museum, Belfast
University Museum, Oxford
And Mr Wood's Fossils, Edinburgh
References
Miller, H (1841) The Old Red Sandstone, London
Peacock, JD et al (1968) The Geology of the Elgin District, Memoir of the Geological Survey Scotland
Traquair,RH (1895) The extinct vertebrate animals
of the Moray Firth area. In JA Harvie-Brown and TE Buckley, Vertebrate
fauna of the Moray Basin. Edinburgh
Text adapted from ##Under construction##
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