Thos, Davidson—Brachiopoda of Brittany and 8. Devon. 339 
and which along with Lingula Morierei, Tromelin, are all species 
that occur in the quartzites and sandstone pebbles of Budleigh 
Salterton. 
Above the “ May Sandstone,” in Brittany, we come upon a deposit 
of slaty schists, which, however, contain but a few Brachiopoda, and 
these in an unsatisfactory and crushed or distorted condition. 
The Silurian Brachiopoda hitherto discovered in the Budleigh 
Salterton pebbles may, therefore, be arranged in the following strati- 
graphical order : 
Lingula Morierei, Tromelin. 
Terebratula? sp. 
Nucleospira Vicaryi, Dav. 
Grés de May—Caradoe Orthis Berthosi, var. erratica, Dav. 
Orthis pulvinata, Salter. 
O. Valpyiana, Dav. 
\ O. Budleighensis, Dav. 
Lingula Lesueuri, Rouault. 
Grés Armoricain—Lowest L. Hawkei, Rouault. 
portion of Llandeilo. L. Salteri, Dav. 
Dinobolus Brimonti, Rouault, sp. 
A Lingula much resembling L. crumena has also been discovered 
at Budleigh Salterton, but it may possibly be a malformation of 
L. Hawkei. Above the Lower Silurian deposits of Brittany, we 
have a large development of Devonian sandstones, quartzites, and 
limestones, identical in mineral composition and colour with that of 
the “Pebbles” of Budleigh Salterton; but it is in the Lower 
Devonian Sandstone of that country, or that named “Grés A Orthis 
Monnieri” by M. de Tromelin, that we find the larger number of 
species that occur likewise in the Budleigh Salterton pebbles. The 
Orthis Monnieri, Rouault, is the shell which I described in 1869 by 
the name of Orthis Viearyi! It occurs in the yellow sandstone at 
St. Aubin d’Aubigny and at Gahard. We have, besides this species, 
in the same rock, Spiriferina octoplicata, Rhynchonella elliptica and 
others. 
I have made out some twenty-eight species of Devonian Brachio- 
poda as occurring in the Budleigh Salterton pebbles, and M. de 
Tromelin has pointed out among them the presence of Orthis Hamoni, 
Rouault, a species recently figured by Mr. Bayle, and which occurs 
also in the Devonian sandstones of Brittany. 
It is quite true, as was remarked by Mr. Peach and Mr. Etheridge, 
that we find in the Lower Silurian rocks of Cornwall bands of a 
light grey quartzite, with casts and impressions of Orthis Budleighensis, 
and that pebbles of a similar nature and with the same fossil are to 
be found at Budleigh Salterton; but when we consider that out of 
the twelve species of Silurian Brachiopoda that are found in the 
“pebbles,” only one, or at most two, of the species occur in the 
* Out of the thirty-six new species of Brachiopoda merely named or briefly described 
by Marie Rouault, only one was figured by him, viz. the Orthis Berthosi. This want 
of illustrations has been the cause of much unavoidable misconception and errors in 
identification. The public had not even the advantage of being able to consult the 
original types, which are not exhibited in the Museum at Rennes, 
