106 | GEOLOGY OF OHIO. 
Ft. In 
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Place of “Great Vein,” which is wanting here, usual interval (45 to 60 feet). 
The Norris coal has so long and so uniformly been counted the 
seam below the Bayley’s Run coal, that a few statements in regard to 
the seam are called for at this point. 
Andrews first assigned a place to this seam (Geol. of Ohio, Report 
of Progress, 1869, p. 119). In vol. III, p. 851, he refers the determina- 
tion of interval to his assistant, Mr. W. B. Gilbert, by whom a measure- 
ment of 46 feet was obtained between the “Great Vein” (Middle 
Kittanning) and the Norris coal. Having already assigned a place to 
the well-known Bayley’s Run coal, 75 to 100 feet above the main coal, 
the Norris coal became the middle seam. When numbers were applied 
to the coals, and the Middle Kittanning become No. 6, and the Bayley’s 
Run coal No. 7, the Norris coal was styled No. 6a. This number was 
afterwards changed to No. 66 in my report on the Hanging Rock 
District, vol. III, on the ground that a regular seam occurs at 25 to 30 
feet above the Nelsonville coal, while the Norris coal was counted as 
coming in at 45 to 55 feet above that seam. Andrews also in his later 
work seems disposed to give a place to a seam between his Norris coal 
and the Nelsonville seam (vol. III, p. 851). 
Truths and errors are so interwoven into all of these accounts that 
the disentangling of them would be a tedious task. ‘There is in some 
parts of the field a thin coal between the Middle Kittanning ind the 
Lower Freeport coals. It is not certain, however, after all that has 
been written, that this seam occurs in the Hocking Valley field. The 
varying intervals of the Lower Freeport and the Nelsonville coals may 
account for all of the facts. The name Norris coal has been so unfor- 
tunately applied that it will serve geological order to drop it altogether. 
The facts, as at present seen, are as follows: 
The two Kittanning and the two Freeport coals maintain their 
horizons with great regularity throughout the Hocking Valley coal 
field. The Kittanning coals are the steadiest of all our coal seams, and 
the upper of the two is by far the most valuable seam of the Lower 
Measures. The coal seams of the Freeport Group are exceedingly un- 
certain and irregular in the large way, but the upper seam gives rise to 
many fine local developments of coal, the most extensive and valuable 
