The district of Strath Errick and Foyers, with which the investigation recorded here is concerned, occupies about 70 square miles southeast of Loch Ness, in Inverness-shire. The ground rises steeply from the loch to form a bordering ridge, beyond which it slopes more gently to Strath Errick. Further to the south-east, the hills rise to a height of 2,560 ft. in Beinn Bhuraich. The country is chiefly moor and hill grassland, with numerous exposures of rock; fairly extensive areas are under arable cultivation in Strath Errick. The district is drained by the Rivers Fechlin and Farigaig, both of which enter Loch Ness through deep gorges (Text-fig. 3).

A Summary of the stratigraphy of the Coal Measures in the Kent Coalfield was given by H. G. Dines in 1933, accompanied by notes on the fossil flora by R. Crookall and on the fauna by C. J. Stubblefield. It was shown that the Coal Measures could be divided into a Lower or Shale Division, some 700 feet thick, consisting mainly of shales with some thick coals, and an Upper or Sandstone Division, about 2,100 feet thick, consisting mainly of sandstone with a few mostly impersistent coal seams, except in the highest part where again there are shales with coals (Dines, 1933, p. 22); the dividing line was taken at the base of a sandstone usually about 100 feet below the Millyard Seam. Recently the correlatable seams in the coalfield have been designated by means of numbers in downward succession and seams numbered 1–6 lie in the Sandstone Division, and numbers 7–14 in the Shale Division (Dines, 1945). R. Crookall regarded the Upper or Sandstone Division as representing the StafFordian and part of the Radstockian series, while the Shale Division he referred to the Yorkian (Text-fig. 1).