F. R. G. Reed — Fauna of L. Devonian of Torquay. 299 



summarize in a graphic form the ideas here put forward and to 

 construct a genealogical tree of the igneous rocks and their related 

 ore-deposits, tracing their descent by successive steps from a 

 hypothetical primitive magma, through various stages of 

 differentiation to the innumerable and varied types that we see 

 to-day. This must be regarded, however, as merely an attempt, 

 and must not be taken too literally, since the data available are as 

 yet insufficient for dogmatism on many points. As already stated 

 the whole question of the actual ^jhysical mechanism of differentiation 

 is still sub jucUce ; between the diverse opinions expressed by eminent 

 authorities it is as yet too early to decide. The fact remains that 

 some sort of splitting of rock-solutions must have occurred ; that 

 is not disputed by any one, bat it is improbable that we shall ever 

 be in a position to state exactly what has happened in every case. 

 Nevertheless, it is clear that these processes, whatever they were, 

 have been the dominant factor in the origin and primary distribution 

 of the deposits of the useful metals on which so much of the world's 

 industrial development depends. 



Notes on the Fauna of the Lower Devonian Beds of 



Torquay. 



By F. R. CowPER Reed, Sc.D., F.G.S. 



Part I. 



(PLATE IV.) 



Introductory RemarTcs. 



/^UR knowledge of the fauna contained in the Lower Devonian beds 

 ^^ of England is extremely imperfect and unsatisfactory, partly 

 owing to the scantiness of the material which has been collected, 

 and partly to the poor preservation of most of the fossils themselves. 

 The lists of genera and species given in the Survey memoir (Explan. 

 Sheet 350) dealing with the Torquay district are not extensive, 

 and in many cases the determination of the species or even the genera 

 is open to doubt. Correlation in detail with the well-established and 

 richly fossiliferous Lower Devonian of the Continent is almost 

 impossible in such circumstances, but Kayser in 1889, on the strength 

 of the palaeontological evidence which he obtained on the spot, 

 correlated the beds at Meadfoot with the Lower Coblenzian.^ The 

 fossils which he collected and identified from this locality were the 

 following Rhenish species : Zaphrentis oolitica, Rhynchonella 

 daleidensis, Chonetes sarcinulata, Spirifera hysterica, Sp. paradoxa, 

 Strophomena cf. Murchisoni, Pterinea costata. 



Classification of the Lower Devonian Beds of Torquay. 

 The division of the Lower Devonian of the Torquay district into 

 a lower portion termed the " Meadfoot Beds " and an upper portion 



1 Kayser, Neues Jahrb. i. Min. Geol., 1889, i, p. 188. 



