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BRITISH DEVONIAN BRACHIOPODA. 



beds were apparently, in general, species in which the fold and sinus were smooth ; but the 

 fragment attributed to Sjj. aperturata shows that at least one of the forms of the genus 

 was provided with ribs on the sinus and fold. 



Orthis granulosa is still an uncertain or not sufficiently made out species ; it is said 

 by Phillips to occur at Woodabay, and some very imperfect casts found by Mr. Valpy at 

 Heddons Mouth may possibly be referable to that species. Phillips mentions also Orthis 

 interlineata as a Linton species, but of this I have seen no examples from that locality. 

 The distinguished Oxford professor divides the Linton group into a lower, middle, and upper 

 part, and states his so-termed Orthis longisulcata was found in the lower part, near 

 Watersmeet and Lynmouth, and in the upper part near West-Lee ; but the specimens so 

 named were so imperfect and distorted that I could form no decided opinion as to their 

 true shape and character. Some fragments also seemed to be not unlike Orthis striatula. 

 Hence further search among these Linton beds would be very desirable, for out of eight 

 or nine so-termed species of Brachiopoda supposed to occur, but five or six distinct forms 

 appear to me to have been hitherto sufficiently established. 



Zone II would extend from about Little Hangman to a short distance beyond Ilfracombe. 

 It commences upon the east side of Coombe Martin Bay ; and probably, with beds 

 containing large and weathered examples of Stringocephalus Burtini, which are said to 

 occur under Little Hangman. These beds are very hard to open, being silicates of lime 

 and iron, or clay-iron- stone, and from which it is most difficult if not impossible to 

 obtain a good fossil. 1 Here, therefore, we would have true Middle Devonian beds, 

 and perhaps at Coombe Martin Bay some representative of the Stringocephalen-Kalk of 

 the Germans, or beds which Mr. Salter would refer to the Lenne-Schicfer and Eifel-Kalk of 

 that country. This region has been recently studied by Mr. Valpy, who has kindly 

 furnished me with many valuable unpublished notes upon the subject, but from which I 

 can extract but the following passages : — " The prevailing rock of the Ilfracombe group is 

 an argillaceous slate of varied texture, generally rather soft and friable, but occasionally 

 firm enough to be used for roofing-purposes, for which it is quarried at Woolscot, &c. It 

 is intersected by numerous beds of sandstone and every kind of grit, from a fine-grained 

 laminated quartzite, to a rough siliceous rock almost approaching to conglomerate, and in 

 colour from <i pale-cream, to grey, blue, and decided red, as at Widmouth. There are 

 numerous intermittent beds of limestone through its whole course, and perhaps the 



1 Mr. Valpy informs me that he lias seen large blocks with weathered impressions of small String. 

 Burtini, on the west side of Coombe Martin Bay, about a mile west of Hangman, in hard impracticable 

 sandstone, and that the east coast of L Coombe Martin Bay wants much examination. There are many thick 

 beds of sandstone, with slates occasionally fossil-bearing ; and round the point, we come to the tough 

 siliceous sandstone with large St. Burtini, close to which are the Red Quartzose Grits, containing the 

 Natica and MijaJina of the Hangman and Iloldstone. I have not myself had the advantage of, as yet, 

 seeing a determinable specimen of Stringocephalus from Coombe Martin, but its occurrence has been 

 mentioned by various authors. 



