Conglomerates, and Marls of Devonshire. 
21 
represent an upper portion of the Llandeilo Flags, or the Caradoc 
Sandstone, or, though not quite so likely, the Lower Llandovery 
Rocks ; and that, like the pebbles in question, the Normandy beds 
are quartzites ; so that there is the closest lithological as well as 
palaeontological resemblance between the two series. 
The difficulty, just hinted at, of establishing the exact co-rela- 
tion of the Norman with the British Silurian deposits, arises from 
the fact that the Silurian fossils of this country belong to what is 
known as the Scandinavian type, which is traceable along the 
•whole northern zone from Siberia to Canada ; whilst those of Nor- 
mandy represent the mid-European type, of which, so far as is 
known, no example occurs in situ in Britain, excepting, possibly, 
the Cornish district previously mentioned. To account for this 
remarkable fact it has been supposed that a broad barrier of land, 
running east and west along the line of the Bristol Channel, so 
effectually separated the Lower Silurian seas of the Scandinavian 
area, including what is now Wales, from the contemporary mid- 
European waters, which embraced what are at present known as 
Devonshire, Cornwall, Normandy, Brittany, Spain, and Bohemia, 
as to prevent the commingling of the marine organisms of the two 
provinces. Mr. Salter is of opinion that the arguments in favour 
of this tract of land, in the Silurian era, are supported by the 
phenomena of the Budleigh Salterton pebbles. Accepting this 
hypothesis, the probability of finding fossils common to the two 
areas is no greater than that of meeting with the same organisms 
in the Red Sea and the Mediterranean, or in the Caribbean Sea 
and the Bay of Panama ; that is, unless it can be shown that in 
earlier periods of the earth's history organic provinces were very 
much larger than they are at present. 
Whilst the palaeontologist just named has no doubt that to find 
rocks in situ containing the fauna of the pebbles we must now 
cross to the coast of France, he supposes that similar beds once 
existed much nearer to south-eastern Devonshire. I confess, how 
ever, that I am, by no means, convinced of a close proximity, for 
