MOUNTAINS AND THEIR ORIGIN. 
97 
also England, Ireland, and Scotland; and his 
Ultima Thule is, no doubt, the Hebrides of our 
days. 
Our present notions of the past periods of the 
world’s history probably bear about the same re- 
lation to the truth that these ancient geographi- 
cal maps bear to the modern ones. But this 
should not discourage us, for, after all, those 
maps were in the main true as far as they went ; 
and as the ancient geographers were laying the 
foundation for all our modern knowledge of the 
present conformation of the globe, so are the 
geologists of the nineteenth century preparing 
the ground for future investigators, whose work 
will be as far in advance of theirs as are the de- 
lineations of Carl Bitter, the great master of 
physical geography in our age, in advance of the 
map drawn by the old Alexandrian geographer. 
We shall have our geological explorers and dis- 
coverers in the lands and seas of past times, as 
we have had in those of the present, — our Co- 
lumbuses, our Captain Cooks, our Livingstones 
in geology, as we have had in geography. There 
are undiscovered continents and rivers and in- 
land seas in the past world to exercise the inge- 
nuity, courage, and perseverance of men, after 
they shall have solved all the problems, sounded 
all the depths, and scaled all the heights of the 
present surface of the earth. 
5 a 
