1 84 TEE POPULAR SCIENCE MONTHLY 



EARLY GEOLOGICAL WOEK OF THOMAS NUTTALL 



By Dr. CHARLES KEYES 



DES MOINES, IA. 



WHEN", in England about a century ago, earth-study was made a 

 modern science through William Smith's famous geological dis- 

 coveries that the relative age and natural sequence of rock-layers were 

 susceptible of accurate determination by means of the contained organic- 

 remains, America very early, and from a wholly unexpected quarter, 

 furnished important aid in support of the newly established principles. 

 The circumstances were long since all but forgotten. In the few casual 

 references made to them in latter years either their significance was mis- 

 understood or familiarity with the attendant conditions was entirely 

 wanting. As the first successful application of modern geologic prin- 

 ciples in the New World the episode must ever remain of greatest his- 

 toric interest. 



Singularly, this primal American effort to correlate by their faunal 

 contents geologic formation widely separated geographically was not 

 made in that portion of our continent which was most accessible and 

 where "it was most natural to expect it — that is, along the well-settled 

 Atlantic border — but it was in the then remotest section of the upper 

 Mississippi valley. First fruits of research and observation were ob- 

 tained in a region which was then perfect wilderness, but which now 

 forms part of the great and populous state of Iowa. Moreover, these 

 remarkable observations were made within a decade of the time when the 

 novel method was originally announced in England. They antedated by 

 fifteen years Samuel Morton's similar effort on the Tertiaries of our 

 Atlantic coast commonly regarded as the maiden attempt in America 

 along these lines. By two decades they were in advance of the first 

 work of that pioneer American paleontologist, Lardner Vanuxem. They 

 anticipated by a full generation the famous investigations of Thomas 

 Conrad and James Hall in New York. Indeed, they were the means of 

 actually and correctly interpreting the true position and biotic relations 

 of the Carbonic rocks of the continental interior a half century before 

 their geologic age was otherwise generally admitted. The Mississippian 

 limestones, as the rocks are now called, remain to-day as compact and 

 as sharply delimited a sequence of geologic terranes as they appealed 

 when first recognized in that memorable summer of the year 1809. 



This successful use in America of faunal criteria for purposes of 

 solving problems of geologic correlation and of identifying geological 

 formations was the first real ray of modern light to penetrate the strati- 



