6 PROF. E. J. GARWOOD AND MISS E. GOODYEAR [vol. lxxiv,. 



in a general westerly direction, although there is always the 

 possibility that the beds may be inverted, especially in the 

 northern half of the district, where the apparent dip is often 70° or- 

 more. The problem is further complicated by the presence of a 

 series of faults which traverse the district in a more or less easterly 

 direction, rendering it difficult to correlate beds in the northern 

 portion of the district with those in the south. 



A visit to the quarry below the Harp Inn or, still better, to^ 

 Gore Quarry, at the north-eastern end of the district, where the 

 shattered character of the rocks is Avell displayed, shows the 

 impracticabilit} 1 " of attempting to trace the individual beds of 

 the series for any distance. 



The grits and greywackes. — The bulk of the deposit is 

 composed of grits and fine-grained greywackes, true conglomerates 

 being subordinate and only of local occurrence. In places, how- 

 ever, the grits become coarse, and may then contain a few small 

 pebbles, but these coarse grits do not differ essentially from the- 

 material which forms the matrix of the true conglomerates. 



The typical pink grits are well exposed in the outcrops round 

 St. Stephen's Church and on the west side of Harp-Inn Quarry. 

 They are much shattered, and often assume a breccia ted appearance, 

 the angular fragments being set in a fine dark paste which contains- 

 a considerable proportion of ferruginous material. The finer grey- 

 wackes vary considerably in colour. The prevailing tints of the 

 fresh rock are various shades of pink and green ; the rocks, how- 

 ever, frequently weather to a buff colour, owing to the hydration 

 of the iron oxides to limonite. Occasionally, fine bands of a 

 bright crimson tint occur, which owe their colour in part to the 

 presence of manganese salts ; one such band may be seen cropping 

 out on the track that leads past the quarry beside the Harp Inn. 

 The presence of these highly -coloured bands is interesting, as- 

 similar rocks have been mapped by Prof. Charles Lapworth in the 

 Bayston Group of the Longmyndian Series, in the type-district 

 farther north. 



A rather different kind of rock occurs in the old quarries below 

 Yat Wood, close to Dolyhir Station. Here the beds dip at 50° 

 west-north-westwards, and consist of compact green micaceous grey- 

 wackes interbedded with layers of crushed shale. The mica-flakes 

 are arranged in parallel layers along the bedding-planes of the 

 deposit, and the finer shale-bands resemble very closely the Strettoiv 

 Shales of the Longmynd area. Some purple layers also occur, 

 which, in addition to mica-flakes, contain a few included fiat pellets- 

 of a red-brown mudstone lying parallel to the bedding-planes. 

 These layers are identical in appearance and structure with rocks 

 exposed in Sharpstone Quarry, near Bayston. A further exposure 

 of red mudstones. containing abundant mica-flakes, also associated 

 with micaceous green greywackes, occurs in Gore Quarry. Tin 1 

 rocks, however, are so crushed and broken that their true dip cannot 

 be determined here. 



