206 GEOLOGY OF SHROPSHIRE. 



Diplogmpsus jyristis, His., Ort]ii!i trutiidinaria, Dalm., and othei* Cambro- 

 Silurian fossils; and as these slialea are very similar in lithological 

 characters to the shales at Shineton, and have the same general strike, 

 both shales were lumped together by him as Lower Caradoc. This 

 lithological resemblance is evidently the chief cause of the errors of the 

 surveyors. On closer inspection, however, it is seen that the shale at 

 Harnage contains a distinct fauna from the Shineton shales. The most 

 abimdant fossils of the Harnage shales, collected near Broomcroft and 

 in the Harnage and Cound-Brook area, are Trmucleus coneentricus, Eaton, 

 Beyrichia complicata, Salt., Primitia hicoriiis, R. Jones, OrtJiis te-'itudinaiia, 

 Dalm., Theca, several species of Lamellibranchs, Diplo/ji-apsus i)ristis, His., 

 and Favosites fibromis, Goldf. These are common Caradoc forms, and it 

 is perfectly clear that the shales containing them are of Caradoc age. 

 In no case are these fossils found in the same beds as those which 

 contain the older fauna presently to be described. It is necessary to call 

 attention to this point, as the Rev. J. D. La Touche, president of the 

 Caradoc Field Club, in his annual address in February last, has 

 suggested some criticism on my conclusions, basing it on a supposed 

 admixture of the older and yoianger faunas. There are no signs 

 whatever of such admixture. The Tremadoc fauna ends abruptly 

 upwards ; the Caradoc fauna ends abruptly downwards ; and not a 

 single distinctively Axenig or Llaudeilo species has been found in the 

 district. 



The Caradoc rocks of this area are much disturbed and faulted, 

 and on Cound-Brook they are inverted, the older resting on the younger 

 at a considerable angle, and, in one or two spots, Shineton shales are 

 strangely wedged in between Harnage shales. Further details may bo 

 seen in mj^ published paper (p. 656) ; but the Caradoc formation in South 

 Shropsliire deserves to be the subject of a separate memoir, recent 

 observations having considerably modified some of the conclusions of 

 Aveline and Salter. 



The Shineton Sn.viiES. 



The locality where I first observed these shales is the spot near 

 Shineton marked on the Geological Survey Map with an arrow dipping 

 to the south-east at 50°. The rocks are there exposed in two good 

 sections on the left bank of the stream. It is from these sections that 

 most of the characteristic fossils have been obtained ; and I have, there- 

 fore, named the formation from this locality. 



1. — Area. — These shales cover an area extending from near Evenwood, 

 on the south-west, to within a mile of Wellington, on the north-east, 

 a distance of eight miles. Their greatest breadth, from Sliinetou to 

 Dry ton, is about two miles ; but where they range towards Wellington it 

 is contracted almost to a point. The area is roughly triangular in shape, 

 the apex of the triangle pointing to the north-east. Its north-west side 

 is bounded by a fault or faults for probably its entire length, various 

 formations from the Hollybush Sandstone to the Trias abutting against 

 the shales. On the south-east side the triangle is covered in by intrusive 

 basaltic rocks for one-third of its distance from the apex, and the 

 remainder by the May Hill Sandstone. The base of the triangular area 



