Gold and Other Minerals in lozca. — Calvin. 365 
bottoms of the modern seas.. Such rocks contain no gold-bear- 
ing veins, and hence it must be obvious that there can be no 
lode mining for gold in Iowa. In the second place, free gold 
occurs in placer mines. Placer mmes are simply sheets of dis- 
integrated rock material which has been strewn over the sur- 
face, usually along river valleys, by the action of flowing water. 
The rocks of mountains decay and are worn away by air, storm 
waters, frosts and other agents ; the gold-bearing veins, if there 
are any, decay with the rest ; the gold is freed from the matrix 
in which it was embedded, and the loose materials, gold and all, 
are gradually washed down to lower levels. The placer miner 
simply separates — by some convenient device — the gold from 
the loose clay and sand and gravel with which it is accidentally 
associated. It must again be obvious that, except in regions 
where there are gold-bearing veins, there can be no placer 
mines worth considering. From all this it will be easy for any- 
one to estimate the probability of finding gold in such a state as 
Iowa. 
In apparent contradiction of all that has just been said it 
must be acknowledged that gold is occasionally washed out of 
the sand banks and river gravels within the limits of our state. 
Spread over the sedimentary rocks and forming our soils and 
subsoils, are sheets of drift which were transported and dis- 
tributed by glaciers coming from the north. Some of the ma- 
terials forming the drift at any given point were carried long 
distances, from away beyond the national boundary. In north- 
ern ^Minnesota and on the other side of the boundary line, m 
the Rainy Lake region, are quartz lodes carrying free gold. 
The ice sheets brought disintegrated materials from this region, 
as they did from all others over which they passed, and spread 
them out as part of the drift of Iowa. Some particles of gold 
came with the rest, and it is possible occasionally to discover 
some of them by panning carefully the loose surface materials. 
A resolute, industrious man, working persistently year by year, 
might possibly accumulate one or two dollars' worth in the 
course of a lifetime; but the business cannot be recommended 
as a profitable means of employing one's time. The resident 
of Iowa who imagines he has discovered a gold mine on his 
home farm is certainly basing his judgment on deceptive ap- 
pearances of some kind. 
