2 
MODERN GEOLOGY IN AMERICA 
effort at correlation by means of their fossil contents of rock 
formations widely separated geographically was not made in that 
portion of our continent which was at that time most accessible, 
and where it was most natural to expect it — that is, along the 
well-settled Atlantic border — but in the then remotest section of 
the Upper Mississippi valley. These quite remarkable observa¬ 
tions and comprehensive generalizations antedated by fifteen years 
Samuel Morton’s celebrated similar effort on the Tertiaries of our 
Atlantic sea-board commonly regarded as the initial attempt in 
America along these lines. By two full decades were they in 
advance of the first work of that pioneer American paleontologist, 
Lardner Vanuxem. They clearly anticipated by an entire gener¬ 
ation the famed investigations of Thomas Conrad and James Hall 
of New York. Indeed, they were the means of actually and cor¬ 
rectly interpreting the true position and the characteristic biotic re¬ 
lations of the Carbonic rocks of our Continental Interior a half cen¬ 
tury before the geologic age of these terranes was otherwise gen¬ 
erally admitted. The Mississippian Limestones, as these rocks 
were finally designated, remained in later years as compact and 
as sharply delimited a sequence of geologic terranes as they ap¬ 
peared when first recognized in that memorable summer of 1809. 
Lewis and Clark had hardly returned from their famous ex¬ 
ploratory expedition through our newly acquired Louisiana Pur¬ 
chase and across the continent to the Pacific Coast before Ameri¬ 
can naturalists began to penetrate this long forbidden garden. 
First of Eastern explorers to reach the confines of that vast sav¬ 
age country out of which before so very long so many great states 
were to be graved, was a Philadelphian, Thomas Nuttall by name, 
whose claims to fame and greatness rest securely upon his many 
discoveries concerning the plants and birds. Nuttall’s scientific 
exploits in the demesnes of botany and ornithology were so signally 
important and so voluminous, that the fact that he creditably 
performed deeds of great valor on the geological field goes almost 
unheeded. 
Curiously enough this earliest geological episode in the West 
is also the most important event in earth-study for the entire con¬ 
tinent during a hundred years. In some of its aspects it is even 
world-wide in its significance. 
Our especial interest in this naturalist, Nuttall, who enables us 
