vr Establishment of the Devonian System 265 



into the Old Ked Sandstone of South Wales, and lie so 

 clearly between the Carboniferous Limestone above and 

 the Upper Silurian formations below. Nor could Murchi- 

 son see a resemblance between that greywacke, or its fossils, 

 and any of his Silurian rocks. With their twisted and 

 indurated aspect, the Devonshire rocks looked so much 

 older than the gently inclined Silurian groups by the banks 

 of the Wye, that both he and Sedgwick thought they more 

 resembled the crumpled and broken rocks of North Wales, 

 and they accordingly first placed them in the upper and 

 middle parts of the Cambrian system. 1 



This correlation, however, was made mainly on litho- 

 logical grounds. The Devonshire rocks were not without 

 fossils, and considerable collections of these had already 

 been gathered by different residents in the county, but no 

 one had yet endeavoured to make a comparison between 

 them and those of known stratigraphical horizons else- 

 where. This task was undertaken at last by William 

 Lonsdale, who towards the end of the year 1837 came to 

 the conclusion that the greywacke and limestone of 

 South Devonshire, judged by their fossil contents, must be 

 intermediate between the Silurian and the Carboniferous 

 formations, that is, on the parallel of the Old Eed Sandstone 

 of other parts of Britain. 



Such a decision from a skilled palaeontologist raised up 

 some serious difficulties, which completely nonplussed the 

 two able geologists who the year before had gone so gaily 

 down to the south-west of England to set matters right 

 there. It seemed to them as if Lonsdale's opinion was 

 opposed to what had been regarded as definitely settled in 



1 Proc. Geol. Soc. ii. (1837), p. 560. 



