88 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
the glacier from Millerstang. The granite blocks would thus have 
formed a middle moraine in the great glacier of the Eden, and instead 
of being transported to the eastern coast of Yorkshire would have 
been transported to the shores of Solway Firth. 
Without insisting, therefore, on @ priori objections to the glacial 
theory, I consider it to be entirely insufficient to account for the most 
important phenomena of distant transport from the Cumbrian moun- 
tains, to whatever extent we should admit the former existence of 
glaciers in that region. It would be useless, therefore, to discuss its 
application to other transported masses of this district. 
§ Diluvial Theory. 
Before I enter upon the application of this theory to the case before 
us, I shall make a few general remarks on the limits of the period 
during which the subaqueous transport of existing blocks may have 
taken place, and the nature of the surface over which they must have 
been conveyed. 
19. Period of Transport of Erratic Blocks.—It appears usual to 
regard the transport of erratic blocks as having taken place only at 
one particular period, and that period one of the latest recognized by 
geologists in the history of our planet. It seems to have been de- 
termined, partly at least, on the principle on which we determine the 
period of deposition of a formation unconformable to those beneath 
it, in which case we conclude the whole formation to be more recent 
than the most recent of those on which it reposes. .The accuracy of 
this conclusion manifestly depends on the assumed faet of the depo- 
sition of the formation having proceeded contemporaneously through- 
out its whole extent. In like manner the period of erratic blocks has 
been assumed to be more recent than that of the tertiaries, because 
such blocks are found to repose upon those formations. There is 
however a great difference between the grounds on which these con- 
clusions rest. We can have no reasonable doubt of the contempora- 
neous deposition of a continuous formation, characterized throughout 
by the same fossils and similar mineralogical structure; but the stratum 
(if we may be allowed such application of the term) of erratic blocks has 
no such character of continuity, and therefore no such necessary con- 
temporaneity in the formation of its several parts, which may on the 
contrary have occupied an indefinite period of time reckoned from the 
transport of the earliest existing blocks from their original sites. 
Blecks which now repose on a recent formation may previously have 
remained for ages on an older one. The only demonstrable conclu- 
sion which can be drawn from the actual position of an erratic block 
is this—that the last stage of its movement was posterior to the for- 
mation of the stratum on which the block reposes. 
A similar conclusion will hold also with respect to gravel contain- 
ing recent organic remains. Its immediate transport to the locality 
which it now occupies must necessarily have been posterior to the 
existence of the animals whose remains are imbedded in it; but we 
cannot possibly apply the same reasoning to prove that-the removal 
