BELISAMA OF PTOLEMY. 371 
it formerly left dry, as the red marl cliffs at 
Blackpool, and the denudation of the submerged 
forests at Crosby and Leasowes induce us to infer. 
This varying sea level at different epochs, may 
naturally be supposed to give rise to correspond- 
ing differences in the descriptions and maps of 
geographers living at remote periods of time from 
each other, and especially, if they were severally 
ignorant of what their predecessors had observed 
and recorded. Without this chain of knowledge 
and collated observation being kept up, the same 
countries, at different periods, may be so describ- 
ed, as to lose almost their identity; for we may 
truly say, with an old topographist, Valans, that 
‘time worketh many alterations, both by water 
and land, and where great rivers did sometimes 
run, now it is utterly drie, and instead of marine 
waters, we have goodly and flourishing meades.”’ 
Leaving, however, and to some other occa- 
sion, any further observations, we would wish to 
make upon the more exclusive geological views, 
connected with this subject; we shall proceed to 
what only of a geographical and subordinately ge- 
ological interest falls within the historical era— 
with the view of noticing and comparing the se- 
