EDWIN JAMES 
281 
River. Of course their eolian origin was then entirely un¬ 
suspected. Well down on the Canadian River he collected fossil 
Gryphaeas and Ostreas from a compact limestone which we now 
assign to the Comanchan, or Early Cretacic, series. He was in¬ 
clined to consider this formation an aberrant phase of the Car¬ 
bonic limestone. In the vicinity of Cape Girardeau, in Missouri, 
he found a fine, white, native argil, as he terms it, the china clay 
of later authorities, which the inhabitants mistook often for chalk. 
One fanciful feature of geological structure, which James ar¬ 
gued for, deserves especial mention. The arch of the Ozarks was 
thought to extend northward along the path of the Mississippi 
River quite to the Dubuque lead mines. The metalliferous beds 
of sparry limestone were believed to be continuous between the 
south Missouri mines and the Dubuque field. As a tenet of 
Western geology this notion long prevailed. Schoolcraft, Feather- 
stonough, and others of their day, adopted it without question; 
but failing to mention James’ ideas in this connection the error 
was perpetuated and generally accredited, by those who came after, 
to these authors rather than the real one. 
The notion that the two mineral districts of the Ozarks and of 
Dubuque were genetically connected in some way is historically 
of very great interest, whoever was the real author thereof. Al¬ 
though Schoolcraf’s report was published first by a year and he is 
often given entire credit for the generalization, his efforts were 
never along the lines of geological structure. He manifestly paid 
little or no attention to the tectonics of the region. And this is just 
what James did do; for he was especially engaged in the gigantic 
task of constructing a structural cross-section across the continent, 
along a parallel half way between the two areas. 
After his Iowa visit Schoolcraft became thoroughly imbued with 
the brilliant notion. He even fancied that the lead-bearing beds 
of the two widely separated regions were geologically in the same 
terrane. His statement was repeated as fact for many years 
afterwards. It is instructive as indicating the crudness of the 
methods of geologic correlation of the day. The conception 
was later elaborated upon from time to time, until its necessary 
consequences had to be finally supported by the assertion that the 
ore-bodies were primarily deposited under the influence of favora- 
