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[Assembly 
time to the air, becomes quite loose in its texture ; and its friability is 
greatly increased. 
SECTION XII. 
Purity of the Ore. 
The portions of the vein adjacent to the walls, especially on the west- 
ern side, are more or less mixed with hypersthene and granular feld- 
spar. The central and eastern portion of the vein, for the space of 300 
feet, is unmixed with stony matter. The layers of rock, which appear 
at the western border, probably belong to the surface, and unless there 
is an exception to a general rule, will disappear, as the mine is worked 
downwards. 
SECTION XIII. 
Exte7it of the Sandford Mine. 
In regard to the dimensions of the vein, it is proper to observe, that 
it is covered mostly with soil, varying in depth, from one to three feet, 
on which there is a heavy growth of timber. It is not uncommon, 
however, to see the ore entirely exposed at the surface. To ascertain 
the whole extent of the vein, as far as was practicable under existing 
circumstances, excavations were made down to the ore, on four trans- 
verse lines, and one in the direction of the length of the vein. Those 
excavations were made sufficiently large to admit of a thorough exami- 
nation, whether of rock or ore, and specimens taken from each, which 
were labelled and numbered on the spot, to prevent any mistake. By 
pursuing this course, I obtained the result, which will be given in the 
proper place. As to the actual width, I give only that, which was ob- 
tained by measuring along the line of excavation, which was made at 
right angles to the vein ; but it is far from being certain, that the west- 
ern limit of the vein was ascertained, as in proceeding west, the accu- 
mulation of soil increased rapidly; the examinations were therefore 
discontinued in that direction. It is not therefore at all certain, that I 
am able to state the actual width of the Sandford Vein. 
By the course stated above, the width of the ore on the main hne of 
excavation, is Jive hundred and fourteen feet, and the length, along a 
line nearly in the centre of the vein, sixteen hundred and sixty-seven 
feet. It then passes beneath tabular masses of rock. Having given 
the width and length of that portion which has been actually examined, 
it is proper to state, that the vein disappears by passing under or beneath 
