| P number: | P519613 |
|---|---|
| Caption: | Specimen of roofing slate from Carmarthen, Carmarthenshire, Wales |
| Description: | Grey-green coloured slate with a relatively coarse-grained rough cleavage surface. The specimen is of Cambrian? age. British Geological Survey Petrology Collection sample number EMC 5787. This coarse texture is unusual for Welsh slate, which is typified by a very fine-grained, smooth cleavage surface. Evidence is known of Roman ruins at Carmarthen where roofing slates have been discovered. This is some of the earliest evidence for slate extraction in the UK. True slate is formed from very fine-grained sediments of bedded clay (mud) and silt, probably laid down on a deep ocean floor. Slight differences in the proportions of clay and silt of different beds are reflected in the quality and appearance of the slate-rock into which the clays and silts are eventually transformed. Sediments deposited in different areas or at different geological times show variations allowing one group to be distinguished from another. Specimen size: 22.5x15cm. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Bain, T.S. |
| Copyright statement: | NERC |
| Orientation: | Portrait |
| Size: | 170.57 KB; 775 x 1000 pixels; 66 x 85 mm (print at 300 DPI); 205 x 265 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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