|Back||Main Details||Samples & Images||Quarries||Usage||References|
Hoar Edge Grit.
Hoar Edge Grit. Basement Beds of the Caradoc Series.
|General Colour Description:||
A yellow/brown colour with moderate flecks of cream/yellow.
|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).
|Reacts dilute to HCl?||No|