150 
AMERICAN GEOLOGY. 
in the midst of the ore. The ore of Sandford lake, at or 
near Adirondack, may be cited as an example of a huge 
mass of magnetic ore in the midst of hyperthene rock, whose 
boundaries have not been determined. It is between 700 and 
800 feet over, measuring from east to west. It extends still 
farther, but the debris and soil is too deep to admit of removal 
for the single purpose of disclosing the extent of the quarry of 
iron rock. 
The masses of ore at Adirondack frequently extend into the 
adjoining mass in branching or ramifying veins, which usually 
terminate in threads or strings, and are therefore lost in the 
rock. At certain points, as I have already remarked, the ore 
rests against the rock, which appears like a wall, but it has 
been observed in many instances, that on penetrating beyond 
this apparent barrier, the ore is found extending beyond it. 
The extension of veins into the hyperthene rock is illustrated 
in fig. 38. Garnets border or fringe the veins lying between 
Fig. 38. 
the rock and ore. These garnet borders seem to have been pro¬ 
duced by the influence of the ore upon the rock. 
The ore of Adirondack produces a remarkably tough iron. 
In the Catalan forge the result is too uncertain, and it does not 
furnish when reduced in this simple way, an iron the qualities 
of which are constant; yet bloomers of intelligence have sue- 
