488 W. W. KiiKj if W. J. Lewis— 



Tlie best sections of the Old Red Sandstones aie in Black Broolv, 

 Saltwells Wood. Here the basal Coal-measuie conglomerate can be 

 seen resting directly on well-bedded purple, green, and bi'owii micaceous 

 sandstones interstratified in a thick mass of puiple with some bands of 

 light-blue marls. One band (south of the bridge) is a pebbly marl. 

 Dr. A. Smitli Woodward has kindly examined a few fossils found, 

 and identifies a large specimen of Onchus Murchisoni (Agassiz) and 

 fragments of various Ostracoderms. The dip is W.S.W. and west 

 at angles varying from 50° to 16°, the steepest angles being on the 

 western side of the strip. At the Leys Colliery, a quarter of a mile 

 to the west, 261 feet below the Thick Coal, they pierced 25 ft. Sin. 

 of dark gritty rock and conglomerate, and then 3 feet of light-blue 

 clunch and 60 feet of red chinch (marl).' The purple beds of Black 

 Brook are nearly 200 feet thick. They clearly occupy a horizontal 

 distance, at right angles to the strike, exceeding 300 feet; and 

 then higher up the hill 400 feet to the east, at Lodge Farm, 

 Downton Sandstones (E'') with Zinc/ulaminiina (common), Modiolopsis 

 complanata, and Beyrichia sp. emerge also dipping west 35°. The 

 brine bath well at Saltwells pierces the Old lied. The Saltwells Old 

 lied compares favourably with this upwards sequence at Tiiuipley, 

 near Kidderminster, 9 miles to the south-west, namely, (1) Temeside 

 Bone-bed, 6 inches; (2) brown and yellow sandstones, 20 feet; 

 (3) purple and green micaceous sandstones interstratified in a thick 

 mass of purple marls. 



Dr. W. Gibson, who has seen the Saltwells succession, points out 

 that purple marls occur in the northern parts of the coal-field between 

 the Millstone Grit and productive Coal-measures. He, however, 

 agrees that it is improbable that the Black Brook purple beds are 

 other than Old lied Sandstone, for they underlie a Coal- measure 

 conglomerate which, according to our mapping, is the same as that at 

 Brewin's Tunnel. Furthermore, within the coal-field the Carboniferous 

 beds die out one after the other as they are followed southward, 

 rendering it more likely that at Saltwells the Lower Carboniferous 

 was removed by inter- Carboniferous denudation, as to which we give 

 some facts below. 



5. The Base of the Carhoniferous System. — lu the Saltwells Claj-- 

 pits the entire sequence from above the Tliick Coal to tlie base of the 

 Coal-measures is exposed. From the bottom of the Thick Coal to the 

 base of the Coal-measures is 190 feet. The lowest of these rocks is 

 a conglomerate to 6 feet thick, passing upwards into yellow grits. 

 The conglomerate varies in thickness, and in places dies out entirely. 

 At Brewins Tunnel there are 28 feet of these grits and the 

 conglomerate in the aggregate. The laminations are oblique. The 

 largest pebble found at Saltwells is 14 by lOA by 7 inches. At 

 Saltwells these beds rest, in various sections, on diiferent parts of 

 the beds we include in the Old Red Sandstone, but in cA'ery section 

 the dip agrees with the underlying rocks. 



At the Hayes, Lye, one can see the conglomerate overstepping the 



^ Silurian System, 1839, p. 478. The lower part of the Carboniferous beds 

 set out in this section crop out in Black Brook. 



