288 F. A. Bradley— Geological Map of the United States, 
are probably Silurian, but not certainly; those of the Indian 
erritory have, as yet, yielded no data for a conclusion ; all 
these are therefore uncolored. 
Sherwood’s results, as published by Hall, will require some 
changes along the north line of Pen nsylvania, in future editions; 
the data did not reach me until this edition had been struck off 
It has long been held that the Appalachian and the Kentucky: 
Illinois coal-fields were formed in entirely independent basins, 
. = ; vl 
while Dr. N ewberry, in conversation, strongly Mier 
far the union continued southward seems difficult of de 
ust pro” 
as that of the 
ck shale, . 
ee imestone a se 
bed was for 
* Dr. R. T. Brown, 1869, letter to the writer. 
