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Local Name(s): |
Harnage Slate, Hoar Edge Grit. |
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Stone Group: | Sedimentary | ||||||
Stone Type: | Sandstone | ||||||
Geology: |
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Geological Sub-Divisons: | Hoar Edge Grit. Basement Beds of the Caradoc Series. |
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General Colour Description: | A yellow/brown colour with moderate flecks of cream/yellow. |
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Hand Specimen Description: | There are two beds, firstly a medium grained, hard, granular sandstone which is well sorted with a rough feel (sample in our collection) the second, a shelly, coarse textured stone which splits along the fossil shells of a brachiopod called Heterorthis subquadrata (Stone Roofing Association: n.d.[a]). Harnage slate is hard and compact at depth, but where it is close to the surface post-glacial weathering has weakened it along the bedding planes inducing a plane of parting. It is this natural parting which renders the rock suitable for roofing. The depth of weathering is no more than about 2 metres in any of the exposures (Lawson 1985: 116-118). |
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Stone Identifiers: | Granular. | ||||||
Reacts dilute to HCl? | No |