File:P213128.jpg

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Waterfall in stream gulley, 750 m. at 278 degrees from Bilfield Farm. Dessication crack casts on the sole of a sandstone in the St. Maughan's Formation. Upward view of the base of a sandstone bed forming a prominent undercut waterfall. Sand has infilled cracks in the underlying mud to form polygonal casts after the removal of the softer sediment. Note that the usually red-brown silty mudstone has been reduced to green at the sandstone contact. Hammer length is 30 cm. The St. Maughan's Formation (Devonian age) consists of mudstones, sandstones and calcretes, the sandstones make up 25 to 35 per cent of the sequence and the cycles are generally thinner. Because of the higher proportion of sandstone, the formation is generally more resistant to erosion than the Raglan Mudstone, and it forms the higher ground in the north-east of the district. Here there are deep stream gulleys with numerous discontinuous sections, the harder beds commonly capping small waterfalls. The formation also forms prominent outliers west of the River Lugg, and there are two small outliers in the south-east at Gains's Hill and Hansnett Wood. In the Bromyard area the thickness is thought to be about 700 m. which may be compared with estimates of 630 m. at Ross-on-Wye, 440 m. around Monmouth and about 400 m. in the Clee Hills.

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current15:54, 14 May 2014Thumbnail for version as of 15:54, 14 May 20141,000 × 660 (287 KB)Dbk (Talk | contribs)Waterfall in stream gulley, 750 m. at 278 degrees from Bilfield Farm. Dessication crack casts on the sole of a sandstone in the St. Maughan's Formation. Upward view of the base of a sandstone bed forming a prominent undercut waterfall. Sand has infille...
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