434 Section of the Alleghany Mountain, ^c. 



or rivulet called Emigh's, to Bald Eagle valley, and Little Bald 

 Eagle creek. The levels have not been taken of this creek, and 

 of the little Juniata, into which it falls, as far as the junction 

 with the Pennsylvania canal, near Huntington ; consequently, 

 until those data be obtained, we cannot fix the precise elevation 

 of the Alleghany ridge, with reference to that canal, and the 

 sea. 



Returning to Bald Eagle valley, at the southern extremity of 

 our section, we will retrace, more in detail, the route I have 

 rapidly sketched. Here we are deep enough to touch the limits 

 of the mountain limestone, although the intervening Bald Eagle 

 ridge separates us from the main body of that formation. Its 

 course is S.V/. parallel with the Alleghany chain, and its pre- 

 vailing dip is E. or S. E. This inclination is inconsiderable at 

 the distance of ten or fifteen miles from the outcrop, and at 

 twenty miles from the Allegha,ny, I have observed its beds to be 

 nearly horizontal. At the foot of the Bald Eagle, or Muncy ridge, 

 they curve up to an angle as high as 60° to 75°, a id occasion- 

 ally may be noticed almost vertical, resting upon their edges. 



Ascending the ravine, by Emigh's run, from little Bald Eagle 

 creek, w^e arrive, in succession, at a variety of sandstone beds, 

 upon which repose the coal measures, unless we view the entire 

 series, as comprehended in the carboniferous formation. These 

 lower beds may be estimated at about thirteen hundred feet, in 

 their aggregate thickness. They are numerous, and as variable 

 in structure, colour, and density, as rocks of this class generally 

 are. Many of them contain casts of producta, spirifers, and 

 unios ; but the prevailing indication of fossils,-is simply the hol- 

 low cavities formerly occupied by these shells. One of the most 

 prominent of the lower beds, is a red, laminated, slightly mica- 

 ceous sandstone, with subordinate seams of red clay and shale, 

 which, after rains, give a red tinge to the surface waters, like 

 those in the red sandstone districts of England. Their inclina- 

 tion is toward the W. and S. W. On some of the subordinate 

 ridges, parallel with the Alleghany chain, and on that side 

 nearest the limestone, the angle or dip of the slaty beds is some- 

 times as great as 60° to the west ; that is, at right angles to the 

 main ridge, and exactly contrary to the prevailing dip of the 

 limestone. 



Hereafter we hope to illustrate with greater precision, the posi- 



