370 DR. A. H. COX OX A L0NG3ITNDIAN [Sept. I912, 



most part badly preserved, as is only to be expected in such coarse- 

 grained rocks. The beds dip at about 5° eastwards, whereas the 

 underlying Dicti/onema Shales dip steeply westwards. The Letton 

 Grits are lithologically very similar to the Hoar Edge Grits of 

 Caradoc, and are probably to be referred to the Bala Series. 



These fossiliferous Letton Grits and Conglomerates differ from the 

 unfossiliferous Brampton Grits and Conglomerates, which are seen a 

 few yards farther up the path, in being less compact and also in 

 the following characters : — Pelsite-pebbles are practically absent, 

 whereas pebbles undoubtedly derived from Cambrian quartzite 

 occur. Such quartzite-pebbles have nowhere been found in the 

 unfossiliferous series. Further, the jointing and bedding of the 

 Letton Grits and Conglomerates are quite regular, and the beds have 

 a gentle easterly dip ; while, on the other hand, the unfossiliferous 

 series, as already mentioned, shows irregular jointing and imperfect 

 bedding with a steep westerly dip. 



The Letton Beds are not exposed at any other point, and so their 

 outcrop can only extend over a few square yards : it is particularly 

 fortunate that there should be an exposure within so limited an 

 area. 



Y. The Steucttjee. 



The members of these three series, Brampton Grits and Conglome- 

 rates, Dictyonema Shales, and Letton Grits, together occupy the 

 whole extent of the inlier, Llandovery Beds being entirely absent. 



The structure of the whole district is that of a broken anticline 

 with an axis running north and south, all the beds on the east of 

 the inlier dipping gently eastwards, and those on the western side 

 dipping up to 40° westwards. 



The inlier itself is bounded on both eastern and western sides by 

 two of the main north-east and south-west faults which are so 

 prominent in Shropshire, although here the direction of the faults 

 is more nearly due north and south. 



The eastern boundary-fault brings against the older rocks Wenlock 

 Shale of typical Shropshire facies, and having everywhere a gentle 

 easterlv dip. From its outcrop this would appear to be a reversed 

 fault. ' 



The western boundary-fault brings on Wenlock Shales and 

 Lower Ludlow Beds. This fault gives rise to a small scarp at one 

 locality, where the Brampton Grits and Conglomerates are brought 

 against the softer Wenlock Shales ; but the direction of its hade is 

 nowhere to be seen. 



The northern and southern boundaries of the inlier must in 

 each case be due to cross-faults, but their position and their 

 direction can only be stated approximately. At the northern end 

 the Biampton Grits and Conglomerates disappear beneath drift 

 along the northern border of Brampton Bryan Park, and the 

 fault in all probability coincides with the drift boundary. On the 

 southern side of the inlier there is no reliable evidence of the 

 direction taken by the fault, owing to lack of exposures and to the 



