Baltimore and the Ohio River. 231 
is in degree somewhat transverse, that as we go south “ the central 
region” approaches the eastern border of the mountainous district, 
and north of the Potomac, that it approaches more nearly the wes- 
tern border, thus crossing the general direction of the mountain ran- 
ges, ata very acute angle. In regard to the agent so efficient in 
throwing up mountain chains, although there is some little difference 
of opinion as to the mode by which it operated, the agent itself is 
now almost universally conceded to be igneous. An opinion that 
gains confirmation, if any is needed, from the occurrence of thermal 
waters along the central line of the Alleghany region. ‘The springs 
at Bath, Va. have a temperature of about 73° Far.; farther south, 
we find the warm springs at 96°; a little farther, the hot springs at 
112°, and still farther the acidulous waters of the sweet springs, 
with a temperature similar to the water at Bath, or about 739%. Far- 
ther examination will, perhaps, discover other and warmer waters, 
along the same line. 
From the preceding remarks, the relation of the secondary rocks 
of the valley of the Ohio and its tributaries, may at once be inferred. 
I have represented them as reposing unconformably upon the edges 
of the transition strata, and I am persuaded that such is their real 
position, although I have lad no opportunity of seeing their actual 
contact. Their proximity and difference in inclination, proclaim that 
such is the case, and their junction could probably be discovered 
within a short distance west of Cumberland, Md. or Bedford, Pa. 
The prevailing dip of the secondary strata, is from N. W. to a litile 
S. of W., subject to some variations, although not greater than would 
reasonably be anticipated. ‘The position of the rocks, may be satis- 
factorily studied by tracing extensive coal beds, where these are 
found cropping out in the perpendicular banks of streams. By tra- 
cing the same bed for a few miles, a slight dip will often be found, 
where none was before suspected. The coal beds of this region are 
equally interesting in a scientific, as in an economical point of view. 
But for want of time, I shall be obliged to postpone for a future num- 
ber of this Journal, some remarks on the subject, that I had intended 
appending to this paper. For the same reason I must postpone the 
examination of many interesting deductions from the foregoing facts. 
I regret very much, that I have not had more leisure to examine the 
primitive and transition strata between Frederick city and Baltimore. 
The confusion and intricacy of the subject, added to my limited ob- 
* Encyclopedia Americana, Art. Virginia. 
