part 1] GATJLT AND LOWER GREEXSAIN'D ]VEAll LEIGHTON. ,45 



incapable, under the present specialized conditions of palseonto- 

 logical science, of doing justice to the matter; and can hope only 

 to convey such information as may indicate the general relationship 

 of the beds and assist the specialist in further investigation. 



Additional Fossils from the Shenley Limestone. 



I have already referred to the great growth of the Walker 

 collection since our former paper was written, and to the pre- 

 paratory work done on the brachiopoda by their late possessoi*- 

 before his death. From an examination of this collection of 

 brachiopoda, numbering very many thousands of specimens, now 

 preserved in the Natural History Museum at South Kensington 

 exactly in its original state, ^ I have been able to cull some infor- 

 mation as to the trend of Walker's later work which, even though 

 provisional and unfinished, is likel}^ to be of service to any future 

 investigator. In all the lenticles of limestone which have been 

 revealed since our former paper, the bracliiopoda have been by far 

 the most abundant element in the fauna, just as they were in 

 those previously discovered. 



Brachiopoda. — (i) In view of the controversy as to the age of the- 

 limestone, it is important to note that the absence of the common Upper 

 Greensand forms, ' Terebratella pectita ' and the typical ' Terebratula bi- 

 plicata,' commented on in our former communication (p. 245), still holds good 

 in the vastly enlarged collection. 



(ii) Determinations mentioned by Walker as having been based on scanty^ 

 material are now much more fully represented : as, for example, Terebratula 

 biplicata Sowerby, var. duteinpleana d'Orbigny (formerly ' a specimen,' now 

 over 20 specimens) ; Rhynchonella antidichotoma Bav. (formerly 'one perfect,' 

 now at least 16 specimens, with others labelled Bh. latissima var. anti-- 

 dicJiotoma) ; Rhynchonella lineolata f?J var. mirahilis nobis (formerly ' a 

 remarkable specimen,' now 4 specimens labelled simply Rh. mirahilis). Most. 

 of the new Shenley species or varieties established by Walker are now very 

 numerously represented in the collection. 



(iii) Some additional determinations have been indicated ; when written 

 in ink, they were probably regarded as final ; when in pencil, as provisional, 

 and requiring further consideration. Among those in ink are — ' Terebratula 

 biplicata, var. ingens nobis ' (many specimens : — a large form diifering from 

 the var. gigantea nobis of our previous paper) ; ' Terebratula n. sp.' (twice ;. 

 two specimens, kept separate) ; ' Terebratula sella var.' (a single specimen, 

 possibly only a deformed individual of some other species ; the collection 

 includes many examples of deformity) ; ' Terebratula obtusa Sowerby ' (one. 

 specimen, labelled 'Greensand above Shenley bed. J. Webb,^ 1904'); 

 ' Terebratulina chrysalis Schlotheim ' (6 specimens : Walker, however, must 

 have felt some doubt about the nomenclature, as he mentioned the occurrence 

 of the form in a letter to me, dated September 17th, 1902, but added, after- 

 the name, ' according to Schloenbach, who refers the Essen (Tourtia) [shells] 

 to this species ' ; and he did not include the name in his list published in_ 

 1903 : see also his remarks on ' Terebratulina ' in L. W., p. 253) ; ' Zeilleria. 



1 Walker sorted the specimens into glass-capped boxes, and wrote his 

 identifications with localities, etc., on the under side. The containing- 

 cabinets were presented along with the collection, which is thus kept intact. 



" The name of one of the quarrymen from whom Walker obtained, 

 specimens. 



