REVIEWS AND BOOK NOTICES. 291 
In his * Sketch of the Structure of the Lower Coal Measures in 
Northeastern Ohio,” Prof. Newberry says that :— 
“It is worth noticing, in this connection, that the Killbuck and 
Tuscarawas run in parallel synclinal valleys, and it seems probable 
that the folding of the strata which formed these subordinate 
troughs and ridges in our great coal basin first gave direction to 
the draining streams of the region we have been considering ; and 
that, in a general way, these lines of drainage have retained, 
already observed, I am prepared to find that the bearings of the 
valleys of the Ohio and all its main tributaries in our State have 
een determined by the same causes that produced the great folds 
of the Alleghany mountains. y 
Another interesting fact in regard to the valleys of the streams 
is, that they are all cut far below the present stream-beds. The 
valley of the Beaver is excavated to a depth of over 150 feet below 
the present water level. The trough of the Ohio is still deeper. 
The Tuscarawas, at Dover, is running 175 feet above its ancient 
The rock bottom of the Killbuck valley has not yet been 
reached, 
The borings made for oil along the streams of the region under 
consideration,-as well as in other parts of the country, afford many 
remarkable facts bearing on this subject. They will be reported 
Siet in detail in the chapter on Surface Geology in our final re- 
por 2 
Prof. Andrews records an interesting discovery, as follows : 
“At Zaleska, in mining the Nelsonville coal, a fine bowlder of 
sray quartzite was found half imbedded in the coal, and the other 
half in the overlying shale. The quartzite is very hard, and 
the bowlder was rounded and worn by friction before it came into 
coal. The dimensions of the bowlder are not far from 17 
: se 
Indicate movement and pressure. Doubtless the bowlder had 
settled into the coal while the coal was in a comparatively soft 
3 ion of the sediments 
which constitute the shale over the coal, is doubtless true. But 
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would hardly have force enough to move heavy bowlders. The 
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