Meyer—Lower Greensand Brachiopods. 253 
which species this form somewhat nearly approaches; I am not, 
however, prepared to say that they are specifically identical with 
T. Boubei, D’Archiac, and must therefore be content, for the 
present, merely to notice their occurrence in our Lower Green- 
sand. 
Some uncertainty appears to exist with regard to the specific 
value of the two or more forms of Yerebratula which, under the 
name of YZ. Yornacensis and varieties, are so abundant at Far- 
ringdon ; for I find that M. D’Orbigny (Prodrome de Paléontologie, 
vol. ii. p. 172) includes the following—T7. Tornacensis, Bouei, 
crassa, HRobertoni, crassificata, rustica, Boubei, Virleti, revoluta, 
subpectoralis, and Keyserlingii, of D’Archiac, amongst the varieties 
of 7. biplicata, Broechi; while Mr. Davidson (Monogr. Cretac. 
Brachiop. pt. 2), on the contrary, appears to consider 7. Tornacensis, 
D’Arch., to be a well established species, perfectly distinct from 
T. biplicata, and of which the following—TT. Roemeri, Bouei, 
rustica, crassa, crassificata, and Murchisoni, are varieties; admitting 
T. Robertoni, T. subpectoralis, and perhaps T. Virleti and T. revo- 
luta, to be specifically distinct from ZT. Yornacensis. Whether 
owing to distorted growth in certain individuals, or to any other 
cause, it is certain that the forms attributed to 7. biplicata and 
T. Tornacensis, in the Farringdon Sponge-gravels, vary greatly in 
size, form, and general outward appearance ; so much so indeed as 
to render it difficult, amongst a large number of specimens, to 
determine whether there are two, or four, or more species present; 
and, as in these specimens the loop is never (?) or very rarely pre- 
served, it is the more to be regretted that so little dependence can 
be placed on those surface-markings of the shell (‘striés d’acroisse- 
ment’) by which M. D’Archiac has distinguished several of his 
(YTourtia) species,—among others 7. Boubei, but which, in the 
Farringdon specimens, appear to be of too fleeting and variable a 
character to be of any appreciable value. That Mr. Davidson is right 
in distinguishing 7. Yornacensis from T. biplicata there can be 
little doubt ; the former being even more closely allied to Terebra- 
tula sella. Some examples of this last species, indeed, in the form 
which prevails in the upper beds of the Lower Greensand at 
Shanklin are scarcely to be distinguished from M. D’Archiac’s 
figures of T. Tornacensis (Mém. S. G. Fr., 2nd. sér. ii. pl. 18, fig. 3). 
Whether or not 7. Boubei should therefore be regarded as a distinct 
species, or included among the varieties of ZT. Tornacensis, future 
researches must decide. 
In addition to those already mentioned the pebble-bed has afforded 
me more or less perfect examples of the following species :— 
Terebratella Menardi, Zam.—A few single valves from the pebble- 
bed, and from the Bargate-stone near Guildford. 
Terebratulina striata, Wahl.—Several specimens from the pebble- 
bed at Tewsley and Hurtmore ; it occurs more frequently in the 
Bargate-stone near Guildford. 7. striata does not appear to have 
been heretofore met with below the Gault. 
