.... The thicknesses of 2448 annual laminae were measured from the Middle Devonian ( c . 388 Ma) Achanarras Limestone Member, Lower Caithness Flagstone Group, and of 2821 laminae from the Mesoproterozoic (1.2 Ga) Poll a'Mhuilt Member of the Stoer Group. Time-series analysis resolved periodicities of 13.8 and 13.9...

... to the lithological association D of Donovan, Foster & Westoll (i 974) and belong to the Lower Caithness Flagstone Group. (3) The Achanarras Limestone (Rayner I963) was sampled at the well known Achanarras Quarry. It consists of laminites comprising alter- nations of microcrystalline carbonate (usually calcite...

... sandstones of the Lower Eday Sandstone Formation, the lowest formation of the Eday Group. Fossil fish are present in this uppermost part of the Rousay sequence, but do not include Osteolepis panderi or Millerosteus milleri and instead are dominantly of species with long ranges in the flagstone sequence...

...Fig. 4 Logged sections illustrating the variability in cycle form. ( A ) A symmetrical cycle from the Lower Caithness Flagstone Group; the central region of the basin, South Head, Wick [ND 376 495]. ( B ) Negative skew from the Lower Strath Rory Group in a marginal region of the basin; Hilton...

... (not shown), a splay of the Helmsdale fault, which parallels the coast a short distance inland. JOHN 0 GROATS SANDSTONE 4kmj UPPER CAITHNESS FLAGSTONE F LOWER CAITHNESS FLAGSTONE t- SARCLET SUB-GROUP 7777777777777772 MEY HAM- SCARFSKERRY LATHERON ROBBERY HEAD LYBSTER HILLHEAD CLYTH TYPE %Ro SECTIONS .OA...

... & Trewin 2010 ) Ham–Scarfskerry Subgroup 177 22 8.05 8.17 (Clairdon Head, Hamilton 1987 ) Latheron Subgroup 114 18 6.33 6.5 (Brims Ness, Donovan 1980 )  Lower Caithness Flagstone Group 2350 Robbery Head and Lybster subgroups 1025 Robbery Head and Lybster subgroups 171 17 10.6...

... 4750m of cyclic Middle Old Red Sandstone lake sediments. This included more than 2300 m of the Lower Caithness Flagstone Group below the Achanarras Fish Bed, and at least 1450 m of the Upper Caithness Flagstone Group between the Achanarras Fish Bed and the mainly fluvial sediments of the John O Groats...

... of the slab containing the chasmataspid. The strata in Achanarras Quarry [ND 150544]; see Trewin (1993 a , fig. 3 )) include the Achanarras Limestone Member at the top of the Lower Caithness Flagstone Group of the Middle Devonian fill of the Orcadian Basin (summary in Mykura 1991 ). The Achanarras...

.... The cyclic sequences of the Lower Stromness Flagstone Formation, which are similar to those of the Upper Caithness Flagstone Group of the Thurso area, are composed of regular intercalations of sand flat, playa, perennial lake and deep lake facies ( Fig. 2 ) reflecting regular climatically...

... ( Wilson 1935 ) separated the full sequence into Lower and Upper Stromness Flags, divided by the Achanarras–Sandwick horizon, followed by the overlying Rousay Flags and Eday Group. Miles and Westoll (1963) correlated the Spital beds of Caithness with the Upper Stromness Flagstone in Orkney, based...

... th Lower Caithness Flagstone Group/Lower Stromness Flags from the Upper Caithness Flagstone Group/Upper Stromness-Rousay Flags. Definition of the top of the Devonian sequence at 1950 m is poorly constrained, given the absence of reliable palynological control above 2029 m. Authigenic illite fractions...

... Caithness Flagstone Subgroup in the Caithness Flagstone Group in the Old Red Sandstone Supergroup of the Middle Devonian. Occurrence. Only in situ and confirmed localities. In Caithness: Cairnfield Quarry [ND153651]; Freswick Bay, a series of fish beds in the bay [ND379671–ND381669]; Lythmore...

... collected from the Southhead Formation of Wick Flagstone Group (Lower Caithness Flagstone Group) exposed in Wick (Donovan et a1. 1974) and from the Thurso Flagstones of the Thurso Flagstone Group (Upper Caithness Flagstone Group) exposed in Sandside Bay, Reay (Crampton and Carruthers 1914, Mykura 1983) (see...

... with frost-shattered platy flagstone clasts, erected in places, occurs below Holocene peat in the Eastern Gulley. This bed has been interpreted as a periglacial slope deposit ( Gordon 1993a ) and can be correlated with gelifluctates of Loch Lomond Stadial age in southern Caithness ( Hall & Whittington...

... of the lacustrine sediments occurred during Eifelian – early Givetian time, represented by the Lower Stromness Flagstone Formation (Orkney), Upper Caithness Flagstone Group (Caithness) and middle Givetian Eday Flagstone Formation ( Fig. 2 ). These lacustrine sediments are characterized within the Orcadian Basin...

...Benjamin H. Tindal; Anthony P. Shillito; Neil S. Davies Abstract Two newly discovered specimens of the fish locomotion trace Undichna ( U. britannica and Undichna isp.) are described from the Middle Devonian Achanarras Limestone Member (Caithness Flagstone Group, NE Scotland). Fish trace fossils...

... coastline, taken to S in June 1989 (acknowledgements to Babtie Group Ltd). The site lies on the north coast of Caithness at Lower Dounreay (about Latitude 58°35′N; Longitude 3°45′W; National Grid Ref. NC 985 671) in a shallow embayment in the coastline ( Fig. 2). The cliffs thereabouts are fairly...

... at this time was at least 12o,ooo km ~. Two stratigraphic mplications arise from the application of a transgression/ regression model to the Orcadian sediments. Some of the alluvial red beds out- cropping in W. Caithness and referred by the Survey to the Barren Group (since shown to be of lower Devonian age...

..., particularly within the Upper and Lower Caithness Flagstone Groups which are dominated by mudstone, siltstone and fine-grained sandstone. These cycles were deposited in basin central positions or close to basin margins where runoV and clastic input were minimal. In basin central areas, such as at Achanarras...