Pebbles of Volcanic Material in the upper Red Sandstone of Morayshire

MFC Paper 01 by SM Ross (1974)

Kilbuiack Castle was situated some 6 km east of Forres. It stood on an oval mound about 60 by 100 m in S129, 200 m northeast of Burgie Distillery (0965 6050). This mound was recently bulldozed to provide material for roadmaking, and proved to be formed not of fluvio-glacial material as first appearance suggested but of deeply weathered felspathic sandstone.
Under some 1.40 m of pebbly soil and till, sections of the weathered sandstone varying in thickness from 1.10 m to 2.50 m were exposed. Near the surface the rock had been weathered to bedded coarse sand with pebbles, but with depth it gradually became a solid but still friable, felspathic sandstone with a texture varying from gritty to pebbly. The sandstone was traversed by regular bands of staining fromiron oxides; in some parts these were thin (1 to 2 cm) but in others from 10 to 30 cm in width. The bands were much more weathered than the paler grey parts of the sandstone and varied in colour from brown through brick red to bright orange. In some bands there was only very fine sand with clay galls.

The abundant pebbles were mostly of quartzite, many being faceted, and one perfect dreikanter was found. A pebble count taken at the southeast edge of exposure gave the following distribution:—

Quartzite 239
Vein Quartz 6
Psammitic granulite 14
Mica schist 2
Dacite 5
Total 266

The presence of pebbles of volcanic material in the old Red Sandstone conglomerates etc of the area is, according to the literature, quite common, This is the only example the writer has come across in many years of systematically searching the known exposures for such pebbles. Thin sections were made of two of the pebbles showing them to be typical dacites, one with spherulitic texture.

Craigellachie Brick and Tile Works

The works was situated on a large deposit of clay just southeast of the village of Craigellachie on the east side of the A941 road leading to Dufftown. It stood on the land which is now Brickfield Farm (292 445).

The present owner, IE Alex Thomson (1974) has in his possession a large photograph of the works taken around the year 1900. It shows two kilns and an engine house with a narrow gauge wire rope railway leading from the clay pit to the works. The pit, which he estimates was some 15m deep, is now almost completely filled with rubbish and levelled with foundation rubble and clay from the newly built council housing scheme nearby and has been planted with grass. The scheme may eventually spread over the whole site.

The photograph also shows some brick-built houses at the roadside which are extant. In addition to producing bricks, tiles and pipes there was a pottery which made such articles as teapots, bowls, flowerpots, umbrella stands and terra cotta work. A typical large drying shed is also photograph, but there is little trace of any of the buildings today.

The Geological Survey said of the clay deposit: “A light brown, laminated glacial silt with horizontal bedding, containing ‘-in layers of fine sand or very small gravel, with occasional pebbles up to inches in diameter, The deposit is about 18 to 20 feet thick. It marks the site of what was once a glacial lochan and occupies a shallow depression in the drift about half a mile.

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