As the gold-bearing mineral beds belong to a series of strata, there is no certainty that the apparent dip of the strata will be the permanent dip of the entire deposit. The probabilities are altogether against such a supposition and in favor of a flattening out as the dip is followed downward toward what must be the center of the basin,, of which a gold prospect should note portions of the rim in the strata. It does not follow that all the strata exposed will reappear when the other edge of the basin is found and explored, because some of them may have thinned out and disappeared in the intermediate space and their place be occupied by others, or the other edge of the basin may not be seen on the surface at any point covered by rocks belonging to later epochs.
When strata thus dip together each other, forming a trough or basin they are synclinal; when they dip away from each other or like the two sloping sides of a roof, they are anticlinal. In the former case, they may rapidly pass out of the limits of a surface claim and enter adjacent ground, in which they may be reached by shafts. In the latter case, they may pass out just as rapidly if only a small portion of the top of the anticlinal fold has disappeared and the location be bases on an outcrop of the flat top of the arch or fold; but as more of the fold has been removed, the dip will apparently be steeper, reaching its maximum half way between the top of the fold and the bottom of the adjacent trough if the folding be perfectly regular. Nevertheless, the last case is scarce.
These remarks are intended to direct the attention of the prospector to the necessity of ascertaining the dip of such discoveries at the earliest possible moment, as a simple matter of self protection, so that the gold prospector may locate the requisite adjacent ground and prevent others from gathering the larger share of the fruits of his labors. Even the simplest tilting of a series of strata, combined with exposure of the outcrop by one stream running with the dip and another across it, may present the appearance of cross veins, particularly if some portions of the outcrop are covered with debris in such way that it is not visible for its full length.
When gold is found outside of fissure veins or contacts, the influence of the rocks on the form of the deposit is more strongly marked. Many gold prospectors have noted the influence which slates exert on lodes, converting them rather into auriferous bands of rock. It is important to mention that when there has been much of this condition, it is important to look for more or less numerous veins parallel to the main lode, which may carry more or less free gold or gold bearing minerals, but being only incidents accompanying the main disruption are less likely to afford the conditions which will develop them into gold veins.