Salter—Budleigh Salterton Pebble-Bed. 7 
tion of the Llandeilo Flags; or lastly, though not quite as 
likely, it may be of the age of our Lower Llandovery rocks, 
—a formation of which, by the bye, we know very little indeed 
as yet. Between these limits (Llandeilo and Llandovery beds), 
the new formation must be placed; but for the present we can 
get no nearer to its actual horizon. 
There is little doubt, that, while our Lower Silurian rocks 
(Llandeilo and Caradoc) were being deposited in the British 
area, a broad barrier separated their sea from that in which 
the contemporaneous French formations were accumulated, 
as Mr. Godwin-Austen has already shewn.* We know this, 
not only by the character of the rocks themselves, which 
indicate, on one side of this old barrier at least, that shingle- 
banks and sand-banks were accumulated, as along a coast- 
line; but the fossils alone would tell the same tale. There 
are abundant Lingule, shells which now only live in shallow 
seas; and numerous Bivalves, allied to the Horse-mussel, which 
resemble most those found a little way below tide-marks ;. and 
great vertical burrows of Worms in the sandy beds speak 
plainly of sandy shores, and not of deep water. 
All this might have been, and would be, compatible with the 
existence of scattered islets in the neighbourhood, while the 
seas might have been of continuous extent. The fact, how- 
ever, that a wholly distinct fauna occupied the French area, 
while that of Wales and the Border Counties was filled with 
our own British types, is clearly not to be so explained. The 
dark earthy slates of Normandy are just like the dark slates 
of Wales; and, on comparing the fossil contents of the two 
regions, we find kindred species in both: but the Trilobites 
and Shells which crowd the famous slate-quarries of Angers 
are only similar to those of Llandeilo and Builth; they are not 
identical in any case. The shingle-banks and _ gravel-beds 
among these ancient beds of ooze contain similar, but not 
identical species on the two sides of the Channel. So of the 
quartzose rocks which overlie them, and which, as above said, 
may represent our Caradoc or our Llandovery sandstones (we 
know not which as yet); their fossils are not the same as those 
of our own area. 
Subject no doubt to the same Peek movement of Seuton 
which converted the bed of the deep ‘ Llandeilo’ sea in Britain 
into shallows and bays during ‘ Caradoc’ times, yet the Nor- 
mandy area has barely a single fossil identical with those so 
widely spread over our own region; the Trilobites are different; 
* Quart. Journ, Geol. Soc., vol. xii. p. 44, &e. 
