24 HS-TKODUCTION. 



map, at least approximately, and assure others that beyond 

 this line it is useless to explore for coal, while within it there 

 is reasonable hope of finding it. 



Again; it is a very common belief that the number of sep- 

 arate beds of coal in every coal region is limited to three. 

 This is also an error. There may in any region be no more 

 than one bed of coal, or even none, although true coal- 

 measure strata are present; or, there may be any unlimited 

 number of separate beds of coal. For example, near the 

 border of the coal-field, where of course the whole formation 

 is thinning out, it is very commonly the case that there is but 

 a single bed of coal existing, even if there be any at all, 

 while farther within the borders there may be several distinct 

 beds overlying each other with other strata between them. 

 With the yet incomplete examination of the coal-field of 

 Iowa, we have identified no less than seven or eight different 

 beds of coal, but we have never found more than two or three 

 of them in the same valley-side or bluff exposure. Explora- 

 tions have not yet progressed far enough to determine how 

 many of them actually overlie each other at any one given 

 point. This must be demonstrated by future enterprise. 



Without wishing to make disparaging reference to any 

 one, it is nevertheless considered a duty to caution the public 

 against a class of persons who go about the country claim- 

 ing to possess great knowledge upon all mining matters, 

 usually giving out that they are " old miners," when if they 

 were really good miners they would have little occasion to 

 bring reproach upon their calling by playing the vagabond. 

 Their object is invariably fraud, as has been too often 

 demonstrated to those who have trusted in them. It is easy 

 for every one to learn who is reliable and worthy of confi- 

 dence, if they will use only the ordinary caution they are 

 accustomed to use in other matters. 



We will close these remarks upon popular errors and 

 illusions, by referring to the fact that whenever we have found 

 a man entertaining extravagant hopes of discovering mineral 

 wealth upon his own land, or upon land he expected to buy, 



