Baltimore and the Ohio River. 225 
we have then undoubtedly the lower secondary coal measures, reposing 
at their eastern edges upon the more highly inclined transition series. 
I say undoubtedly, because the whole distance has not been examined 
by myself personally, my progress westward terminated at Browns- 
ville, on the Monongahela. To that place the rocks continue as I have 
already described, and beyond that I have ventured in accordance 
with analogy,. in accordance with all accounts received of that district, 
to represent the secondary strata, as continuous with those east of the 
Monongahela. These then constitute the formations visible along 
the route—Ist. the primitive series of the immediate vicinity of Bal- 
timore ; 2d. the transition slates, sandstones and conglomerates of the 
adjacent country, and 3d. the lower secondary rocks of the west. — 
We have next to consider the relation which the several strata 
bear to each other, their dip and direction. And in these respects, 
the district we are considering, is peculiarly interesting. It presents 
some seeming anomalies, when compared with other transition dis- 
tricts, in other parts of our country, but these may be mostly referred 
to the fact, that here we have deposits of a peculiarly variable charac- 
ter, on a much more extensive scalc, than can be found at almost 
any other place. It seemed highly desirable to me, to ascertain if 
possible, the range of mountains, that could be considered as the cen- 
tral or anticlinal ridge, if any such existed. With this view, I was 
watchful to note the dip and direction of the strata, at every point 
where these were visible, and when it happened that any considera- 
ble distance was passed over while these essential points remained 
obscure, this absence of positive information was also carefully noted. 
Upon the whole, it may safely be said, that there is hardly a tract of 
equal extent, where the dip and direction are as clear and satisfacto- 
ry, as along the route traversed. ‘The primitive rocks nearest Balti- 
more, exhibit pretty regularly a considerable dip towards the S. E., 
but this soon becomes confused, the strata are seen with a reversed 
inclination, (i. e. to the N. W.) at times also, they are seen nearly 
vertical, and again seemingly piled up unconformably on each other. 
frregular cracks too, traversing compact masses in different direc- 
tions, evince great disorder. ‘These appearances are most striking 
between Ellicott’s mills and the city, west of the mills the dip contin- 
ues more regularly S. E. until we lose sight of the primitive rocks 
altogether. ‘Throughout this whole region the inclination of the stra- 
ta is very great, being often vertical and seldom less than 45°. Af- 
ter entering the graywacke region, the degree of inclination is subject 
to greater variety, the direction of the dip also appears frequently, 
