Yol. 68.] ARDEN SANDSTONE GEOUP OP WARWICKSHIRE. 257 



which flows into the Blythe. On both sides of this valley the 

 Arden Sandstone can be traced, as shown on the Geological Snr"^ey 

 map, the Lower Marls occupying the bottom of the valley and the 

 Upper Marls coming in at about 375 to 390 feet O.D., the strata 

 being practically horizontal. The sandstone in the zone becomes 

 less conspicuous, especially when the beds are followed northwards 

 and westwards, and replacement of sandstone by pale-grey and 

 green shale and marl seems to be taking place. 



The outcrops on either side of the valley do not descend the 

 valley-slopes and unite on the north near Netherwood Heath, as 

 shown (with dotted boundaries) on the Geological Surveys map, for 

 the zone is to be found maintaining its horizontality at Chadwick 

 End on the east, and about Packwood and Dorridge on the west. 

 Along the eastern branch the course of the zone is obscure, owing 

 largely to the presence of drift sands and gravels and red marly 

 boulder-clay ; but from time to time grey marl, mudstone, and shale, 

 with an occasional thin sandstone or skerry, are discoverable 

 about 350 to 370 feet O.D., indicating that the zone is present 

 and that it remains almost flat. The best exposures about here are 

 to the east of Temple Balsall and to the north of Fen End, and it 

 is highly probable that the zone follows the contours of the country 

 approximately as indicated on the map (PI. XVIII). 



The western branch can be joined up with the Knowle Sandstone 

 outcrop. At Chessetts Wood drift sands with overlying boulder- 

 clay are banked up against the zone : but the band is easily recog- 

 nizable at and west of Packwood Church, where it occupies the 

 floor of the shallow valleys. The exposures are not good, and seem 

 to consist entirely of gre}" or greenish shale and marl. The top 

 of the zone about here is, as usual, close to the 400-foot contour- 

 line ; but one of the outcrops running up a valley to the soath-west 

 crosses that contour, and reaches 445 feet O.D. at Sand's Earm, near 

 Hockley Heath. Thick drift obscures most of the ground between 

 Packwood and Knowle. There is, however, an exposure of the 

 characteristic shaly sandstone in the stream and in the roots of an 

 overturned tree, east of Packwood Gullet, which enables the out- 

 crop to be indicated as far as the road at Knowle Grove, north of 

 which, about Ardendale and Jacknet, are several exposures of sand- 

 stone and shale which enable the zone to be linked up confidently 

 with the outcrop mapped by the Geological Survey at Knowle. 



At Knowle some 9 feet of the sandstone zone, resting upon the 

 Lower Marls, is well exposed on the west side of the canal. It 

 consists mainly of pale-grey laminated shales and mudstones, with 

 an occasional thin, flaggy, quartzose and felspathic sandstone band. 

 Near the base is a thin bed of dark-grey clay or shale, and about a 

 foot above the base is a zone full of tiny pebbles, as at Shrewley, 

 in which Mr. Richards (94) found fish-remains and close to which 

 I obtained an ichthyodorulite. About 6 feet higher in the deposit 

 Esilierice are not uncommon. The beds here are well and evenly 

 stratified, and dip gently towards the Rhsetic and Lower Liassic 

 outlier of Copt Heath, about two-thirds of a mile away to the north. 



