147 [Lesley 
1871.] 
They are merely certain strata consisting more or less completely of per- 
oxide of iron, with more or less intermixture of mud and sand, 
which, when crystalized, fell into the shape of feldspar, hornblende, mica, 
quartz, etc., etc. 
To show that this is not mere theory, but actual fact, I compare here 
the section of magnetic iron-ore beds worked out on Durham Creek, 
near Easton, Pennsylvania, a map and sections of which can be seen 
by reference to W. Brook’s part of the New Jersey Geological Re- 
port, by Prof. Cook, 1868, page 332, and given in Fig. 10. 
Fia. 10. 
Ty lo. 
& 
‘S 
/ 
f 
) 
—— Level of tld Tennel 
Bia gs ck Ge cee ‘oa aw 
S& 
Tt follows then from the above mentioned facts : 
1. That the Number of Ore beds in such a formation cannot be 
stated. A large number of rock strata will become ore-beds locally. But 
there will always be a particular part of the formation more generally 
and extensively charged with great quantities (or a high percentage) of 
iron than the rest. In other words, the iron of the formation as a whole 
is concentrated along one or more lines. This is evidently the case with 
the Tuscarora Ore Belt, as is shown by the almost perfect straightness of 
the outcrop of the Sergeant Shaft ore-bed, where its outcrop has been 
opened for half a mile northeast of the shaft. There are two principal 
beds cropping out on the Teague plantation, at the (southwest end of the 
belt), both vertical, and about 300 yards asunder, thus: Fig. 11. 
Fie. 11. 
Or Gah ‘ 
ore a Abbots Groce 
Fram 
Yee Scale 100 yarks Ie Hx inch. Section Liss S.78'¢. —» 
Another instance occurs on the Trueblood plantation (12 miles), where 
the two ore-beds appear to be only about 200 yards apart at their outcrops, 
and seem to dip different ways, which I explain by reference to the false 
surface-dip of the Sergeant Shaft bed. The Trueblood section is as 
follows: ‘ 
