CAilBRIAN ROCKS Itf SOUTH SHROPSHIRE. 661 



palaeontological evidence. This species is common at the base of the 

 Lower Tremadoc of North "Wales, and helps to connect that formation 

 with the Shineton Shales. Taken by itself, the occurrence of a single 

 species may not be decisive ; but when other lines of evidence con- 

 verge to the same point, this fact is of value. 



I have stated that all the species of the Shineton Shales are new 

 but two, Asaphellus Homfrayi and Dictyonema sociale, and perhaps 

 a hydrozoan. It is strange that the fauna should be thus so nearly 

 unique, if beds of the same age and of similar lithological characters 

 (slates being simply altered shales) had been deposited in the same 

 sea ; and that there was a water connexion between the Shineton 

 and Tremadoc areas is evident from the occurrence of two species in 

 common. I would therefore suggest the probability of the Shineton 

 Shales forming beds of passage between the Lingula-flags and the 

 Lower Tremadoc — a probability which is strengthened by the fact 

 that Dictyonema sociale occurs in passage-beds in the Tremadoc area. 



6. Distribution of the Fauna. — The bulk of the fossils have been 

 found high up in the series at Shineton ; but Lingulella Nicholsoni 

 and Obolella sabrince occur almost wherever the shales are fossi- 

 liferous, ranging down to the base of the series near Dryton, where 

 the rocks begin to assume a north-westerly dip. Graptolites are 

 common north of the Severn, their chief habitat being Mary Dingle, 

 near Garmston, but have not yet been found south of that river on 

 any horizon. Trilobitcs have rarely been fouud away from the 

 Shineton section, the exceptions being a single specimen of Platy- 

 peltis Croftii in Mary Dingle, an undeterminable Trinucleoid form 

 from the same locality, Conophrys salopiensis in the arenaceous beds 

 near the top of the series west of Harley, and both P. Croftii and 

 C. salopiensis from Malvern. Macrocystella (a new Cystid) has been 

 detected only at Shineton and on Cound Brook. 



7. Relation to the blaclc Olenus-shales at Malvern. — In the Shine- 

 ton area the shales are lithologically homogeneous from top to bottom 

 (except that they grow more arenaceous towards the top), and never 

 put on the aspect of the black shales. The fossils also show no 

 signs of transition into another formation, Lingulella Nicholsoni and 

 Obolella sabrince characterizing the series throughout its entire ver- 

 tical extent ; and none of the forms are found in the black shales, 

 the three Shineton species, Dictyonema sociale, Conophrys salopiensis, 

 and Platypeltis Croftii being found at Malvern only in the light- 

 coloured upper shales. I am therefore disposed to conclude that 

 the Shineton Shales represent only the Dictyonema-sholes of Malvern, 

 though they have a much greater thickness. There are signs of 

 great unconformity between the Shineton Shales and the Hollybush 

 Sandstone of the AVrekin. In Wenlock Wood, near the Wrekin, the 

 shales dip away in the same direction as the sandstone ; but to the 

 south-west, near Bank's Lane, they dip towards the sandstone to 

 the north-west ; and to the north-east, under Madox's Hill and near 

 Willow Moor, the sandstone dips away from the shale. It there- 

 fore appears probable that the shales are faulted against the sand- 

 stone ; and if the black shales ever existed in the area, they must 



Q. J. G. S. No. 132. 2 x 



