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BRITISH DEVONIAN BRACHIOPODA. 



Lower Devonian. 



Some geologists, among whom I may name Mr. Pengelly, use the terms Lower, 

 Middle, and Upper Devonian, as terms of convenience only, not as equivalents to Lower, 

 Middle, and Upper Old Bed (see pages 44-5 of this Monograph) ; and here we must place 

 all the slates of south-east Cornwall, as well as of Mudstone Bay near Brixham, Galmpton 

 Creek on the Dent, and Meadfoot near Torquay : in fact, all the Pleurodictyum and 

 Steganodietyum beds. The Looe grits (more correctly slates) would be near the top of the 

 Lower Devonian. The term ' Meadfoot Sands' has been erroneously made use of by 

 myself and some geologists. Meadfoot is a sea-beach, hence the word " Sands," the 

 beds in this locality being slates, but they do not appear to contain many species of 

 Brachiopoda. 



Mr. Pengelly observes, that Linton is undoubtedly the base of the Devonian series of 

 North Devon • and unless the beds there are Lower Devonian, there can be none of that 

 age in the country. Murchison ( f Siluria/ Table, page 433, 1859), Lyell ('Elements/ 

 6th ed., page 532, 1865), and Salter ('Quarterly Journal, Geol. Soc, vol. xix, page 489, 

 1SG4), unanimously place them on this horizon. 



Looe, in Cornwall, is a very interesting locality, which abounds in several species 

 of Brachiopoda, but unfortunately only in the state of internal casts and impressions. 

 Those I have been able to examine are the following : 



Athyrist sp. ? PI. IV, fig. 4. Several casts similar to the one figured were found by Mr. 



Pengelly, at Looe; but none of the specimens are complete enough to be 

 determinable. 



Spirt/era primceva, Steininger?? PI. VIII, figs. 1, 2, 3. Described and figured under the denomi- 

 nation of Sp. cultrijugata, Koemer? (p. 3.")). This fine large species occurs un- 

 fortunately in the condition of imperfect casts, no perfect example having as 

 yet been procured. Since the publication of my descriptiou, it has appeared to 

 me that these Looe specimens approach more to Sp. primceca than to Sp. cultri- 

 jugata. The correct determination of this shell must, however, depend on the 

 discovery of better examples. 

 — sp. ? PI. IV, fig. 33. This internal cast is much out of shape from fossilization, but 

 indicates the presence of a smooth species of Spirifera not unlike Sp. glabra. 

 Spiriferina cristata, var. octoplicatal PI. VI, figs. 11, 12, 13, is very common, but rarely well pre- 

 served, so that identification cannot be considered as perfectly certain. 



Atrypa reticularis, Lin. 



Rhynchonella Pengelliana, Dav. PL XII, figs. 8, 9. 



— sp. ? A small form, undeterminable from the material at hand. 



