374 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JimO 19, 



numerous fossils. The limestone bands are worked extensively 

 at Combe Martin, Haggington, and near the town of Ilfracombe, 

 where two species of GyathophyUum are common, and several 

 species of Brachiopoda are also found in a most imperfect state of 

 preservation. 



5th. Morthoe group. This wide group has hitherto yielded no 

 trace of any fossil. Its northern or lower portion consists of slates 

 which do not materially differ from those of the Ilfracombe group, 

 except that the characteristic limestone bands are wanting. The 

 upper beds of the group are composed of micaceous sandstones and 

 conglomerates, nearly all of which are stained a deep-red colour, 

 from the iron-ore with which this southern portion of the series 

 abounds. 



6th. CucuUaea-zone. This bed formed the lower part of the 

 Pilton group of Prof. Phillips, and has been called by both Messrs. 

 Salter* and Jukes t the " Marwood" bed. This local designation is 

 not, however, altogether an advantageous one, and in some cases it 

 is productive of confusion between this group and that which suc- 

 ceeds it, since in the extensive parish of Marwood numerous quarries 

 are worked in the slates of the Pilton beds ; and hence it follows 

 that many of the fossils found at Marwood do not occur in what 

 Messrs. Salter and Jukes call the Marwood beds J. As these sand- 

 stones are in some places a perfect congeries of shells of the genus 

 Cucullcea, it may perhaps be better to follow the example of some of 

 the German geologists, who frequently name a bed after its predo- 

 minant or characteristic fossil §. 



The following are the best fossil-localities in the CucuUsea-bed : — 

 (1) Baggy Point, where the width of the bed is well seen, as the Pro- 

 montory of Baggy is due to the extreme hardness of the sandstone, 

 the component particles of which are united in places with a ferru- 

 ginous cement, and which has therefore greater power to resist the 

 action of the waves than the soft slates lying on either side of it. A 

 thin vein of greenish or olive-coloured shale is situated on the south 

 side of the sandstone, and separates it from the slates of the Pilton 

 group. (2) Sloly Quarry, where there are several beds of olive shale, 

 full of two small species of Lingula. They are intercalated with 

 the sandstone, and are not confined to its southern boundary as 

 appears to be the case at Baggy Point. In this quarry the sand- 



* Quart. Journ. Geol. Soc. vol. xix. p. 479. f Ibid. vol. rsii. p. 347. 



\ Mr. Davidson, in his monograph of Devonian Brachiopoda, mentions the 

 occurrence of the following species at Marwood (as these specimens were from 

 my Collection, I take this opportunity of saying that, although they were found 

 at Marwood, they did not occur in the Cucullsea-sandstone, but in the Pilton 

 slates) : — 



Chonetes Hardrensis. Orthis interlineata. 



Productus prrelongus. Productus scabriculus. 



Ehynchonella laticosta. Ehynchonella pleurodon. 



Spirifera Urii. Strophomena analoga. 



Terebratula sacculus. 



§ A recent British example of this system of nomenclature may also be found 

 in the " Avicula-contorta'' zone of the Eheetic formation. 



