Rocks / Sandstone nodules.( concretions ).

These specimens were collected at a road widening excavation near Enville, Which is a small village between Bridgenorth and Stourbridge. The geology at the point of collection is the Enville member, sandstone, in the Salop formation. The smaller nodule appears to be very hard silica with a flaky appearance. The slab shaped  nodule is composed of small irregular grains of sand.  The larger spherical nodule or concretion is composed of very fine grains of sand, and on examination under magnification has numerous minute blue coloured inclusions, which I think are silica based, and are shown in the inset picture. There is also a distinct reddish ring at it's centre, which could have been the "seed" for the growth.  

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