APPENDIX—GEOLOGICAL SURVEY. <161 
gether with the same relations, action and re-action upon each 
other that we find in the larger fissures and veins that consti¬ 
tute our mineral strata. I obtained, some time ago, a beauti¬ 
ful specimen of this miniature form of mineral veins in a small 
slab of limestone, that represents very forcibly this feature of 
mineral strata. This slab of limestone is deposited with the 
mineral specimens of the lead district, and can be seen at the 
State Agricultural Rooms, Madison. 
In this altered, or prepared rock, the larger fissures in which 
productive mineral veins are found occupy a central position, 
into which these minor fissures or seams seem to fall, or from 
which they seem to diverge. That there is a relation between 
these minor fissures and mineral veins proper, all intelli¬ 
gent miners agree, but what that relation is, is not so clear. 
It is the opinion of a certain class, that these small fissures or 
seams contribute in some way to the productiveness of the 
vein, hence they are called feeders. When a miner sees these 
little feeders, or as they are sometimes called, droppers, begin¬ 
ning to traverse the stratum through which he is drifting, 
especially if they contain ore, he feels that he is almost certain 
of a productive vein. 
It was usual for us in our English mines to speak of a lode 
(or vein) and its branches, as though these little fissures were 
thrown off from the lode like branches from the trunk of a 
tree. This view would lead us to suppose that the vein was 
the source of the branches, instead of the branches being the 
feeders of the vein. This idea, perhaps, has grown out of the 
fact, that these little branches or seams are small, but well de¬ 
fined near the vein, and often filled with material similar to 
the vein itself, but as they recede from the vein they grow less 
distinct, and become lost in the joints and cleavage of the 
rocks. 
These are some of the features of mineral strata as they are 
seen practically. They are not local, but general phenomena; 
are not confined to one class of rocks, fissures or mineral veins, 
but they are the results of general laws that underlie them all. 
They are also the practical miner’s text book, in which he 
