74 ME. G. W. L.VMPLU&H OS THE JUXCTIO^' OF [vol. Lxxviii, 



Bracliiopoda. — Respecting' this Class, it is first necessary for me to take 



exception to an implication by Dr. Kitchin & Mr. Pringle tliat the late 



J. F. Walker was swayed by stratigi-aphical considerations in naming these 



fossils. Their statement is — • They [that is, Lamplugh & Walker] met the 



■ difficulty by explanations ■which we have always considered to be inadequate, 



while they treated as so-called •' varieties '" some of the species which appeared 



to occur so far below their usual horizon. Arguing from stratigraphical 



inferences, they claimed to demonstrate that these species in reality made a 



' miich earlier appearance and possessed a much longer vertical range than had 



' previously been suspected. We need make no lengthy comment here on this 



' manner of dealing with the palaBontological aspects of the bed.' etc. (K.P., 



p. 5.) 



But Walker's attitude throughout, in working on the brachiopoda, was the 

 reverse of that imputed to him. He recognized from the first that these 

 fossils had their nearest analogues in those of the Tourtias, and he was ready 

 to stretch the comparison to bring them within the limits of established 

 species (L.W., p. 247). His previously quoted letter (p. 46) is sufiiciently 

 explicit in this matter, and others of his to me have the same tenour; as, for 

 instance, ' The Zeilleria are very difficult. I don't want to make new species 

 Txnless obliged' (letter, December 28th, 1902), and 'I fear we shall have to 

 make a new species of the Terehrirostra ' (October 13th, 1902. and a similar 

 phrase with regard to the same form in a later letter). 



I know that especial importance has been assigned to the last-mentioned 

 fossil, eventually described and figured by Walker as Terehrirostra lyra 

 (Sowerby) var. incur virost mm nobis, and I will therefore discuss it further in 

 this connexion. T. lyra had long been prized as a rare and curious fossil 

 both in this country and abroad, and the discovery of a shell of this type in 

 imexpected abundance, along with another rarity, Terehratida capillata, in 

 even greater abundance, in the Shenley limestone, provoked Walker's imme- 

 diate interest, and induced him to enter vigorously into the investigation of 

 the bed. Apj)arently Terehrirostra had never before been represented by such 

 richness of material from one place, exhibiting manifold gTOwth- and varietal- 

 phases, and this rendered comparison with the previous scanty material more 

 difficult. There is a species, Terehratxda arduennensis d'Orbigny, closely 

 resembling lyra, occurring in the Mammillatus Beds of the Ardennes ^ and in 

 some of the Tourtias," respecting which Walker wrote to me (January 16th, 

 1903): •' I want a Terehrirostra arduennensis to compare with ours. I have 

 written to [a foreign correspondent] ; he is trying to get me one.' But. 

 apparently, the attempt was ujQsuccessful, as no example of the species is to 

 be found in Walker's rich collection of foreign brachiopoda now in the 

 ISTatiiral History Museum ; and the critical comparison, much to be desired, is 

 probably still lacking. 



It is, at any rate, certain that a Terehrirostra near to the Shenley and Long 

 Crendon fossil has its horizon in the Basement-beds of the Gatdt in France ; 

 and among the five species of this aberrant genus recognized by A. d'Orbigny, 

 one occurs in still older beds, namely, T. neocomiensis d'Orbigny, found in 

 the Lower Cretaceous.^ Consequently, there is nothing astonishing in the 

 appearance of the fossil where we have now found it. 



The following analysis will serve to show the general aspect of the 

 brachiopod-fauna of the limestone. 



^ C. Barrois, ' Terrain Cretace des Ardennes ' op. cit. p. 275. 



2 'Note siir . . . . Terehrirostra, ■&c.' Journ. Conchyliol. vol. ii (1851) p. 222. 

 T. neocomiensis is figured by Zittel to illustrate the genus, in ' Text-Book of 

 Palseontology ' Eng. transl. London, vol. i (1900) p. 331. Another of A. d'Or- 

 bigny's five species, T. canaliculata, is from the Tourtia ; but Davidson con- 

 siders that this form is a true Terehratella, and not a Terehrirostra : see 

 ' Monogr. Brit. Cret. Brachiopoda ' Pal. Soc. pt. ii (1852), footnote on p. 32. 



