The Revised Statutes, in defining the extralateral right, use the terms" entire depth," and "course downward," as a substitute for the terms "dips, angles, and variations." The term "dip" is the one in common use. "Dip" and "depth" are of the same origin, and "dip" and "course "downward" are synonymous. "Dip" is the direction or inclination towards the "depth."

"Strike" does not appear in any of the mining laws. It is the popular term for designating the longitudinal course of a vein such as is indicated by following the apex of a lode of the character shown in figure 4, that is the "length along the vein," as these terms are used in section twenty-three hundred and twenty of the Revised Statutes, which is equivalent to the longitudinal course. The terms "dip" and "strike" have such a mathematical relationship to each other that it is almost impossible to define one without including the definition of the other.

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§ 318. "Strike" and "dip" as judicially definedJudge W. H. Beatty, in his testimony before the pu land commission, thus defined these terms:

"The strike, or course, of a vein is determined by a la ori"zontal line drawn between its extremities at that depth "at which it attains its greatest longitudinal extent. The "dip of a vein, its "course downward" (Rev. Stats., 2322), "is at right angles to its strike; or, in other words, if a "vein is cut by a vertical plane at right angles to its course, "the line of section will be the line of its dip.

"The strike, or course, of a vein can never be exactly "determined until it has been explored to its greatest extent; but a comparatively slight development near the "surface will generally show its course with sufficient accuracy for the purposes of a location. The dip having "an exact mathematical relation to the course of the vein "is, of course, undetermined until the strike is determined;

"but, practically, the line of dip is closely approximated "by taking the steepest the (nearest a vertical) line by which

a vein can be followed downward." 3

1 Duggan v. Davey, 4 Dak. 110, 141.

The miner in locating his claim, although he is called upon to locate it "along the vein," has but little opportunity to explore the ground and determine prior to location what is its course, or strike. He is compelled to exercise his best judgment from surface indications and such primitive development as the limited time allowed him to perfect his location will permit. A vein does not always outcrop to any considerable distance, so as to present to the miner's observation its longitudinal direction. His location usually precedes any extended exploration, and, in most cases, is made without accurate knowledge of the course or direction of the vein.'

Mathematically speaking, the true course of a vein is never demonstrated until after extensive investigation and the expenditure of time and money. In a case decided by Judge Hawley, sitting as circuit judge in the ninth circuit, one of the veins in controversy had been located for forty years, and at different times during that period. the mine was in active operation. At the trial, the course of this vein was a disputed and closely contested question, although there were extensive underground workings.

In addition to this, the lower levels of a mine frequently show a different direction from that which guided the miner in making his location, and are at variance with conditions shown in openings nearest to the surface. This was the case in the famous Flagstaff mine in Utah, where the croppings showed that the direction, or course, of the apex of the vein at or near the surface, was nearly east and west. By following a level beneath the surface, the strike of the vein ran in a northwesterly direction, so that if, by a process of abrasion, the mountain were ground down, the strike of the vein would have been northwest instead of west, as the line connecting the surface outcrops tended to show that it was.

Iron S. M. Co. v. Elgin M. Co., 118 U. S. 196, 204.

2 Cons. Wyoming G. M. C. v. Champion M. Co., 63 Fed. 540, 548. Flagstaff S. M. Co. v. Tarbet, 98 U. S. 463, 469.

Upon this state of facts, the supreme court of the United States thus expressed its views:

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"We do not mean to say that a vein must necessarily crop out upon the surface in order that locations may be properly laid upon it. If it lies entirely beneath the surface, and the course of its apex can be ascertained by sinking shafts at different points, such shafts may be 'adopted as indicating the position of the vein, and loca"tions may be properly made on the surface above it, so as to secure a right to the vein beneath. . . . Perhaps "the law is not so perfect in this regard as it might be; perhaps the true course of a vein should correspond with "its strike, or the line of a level run through it; but this "can rarely be ascertained until considerable work has "been done, and after claims and locations have become "fixed. The most practicable rule is to regard the course "of the vein as that which is indicated by surface outcrop "or surface explorations and workings. It is on this line "that claims will naturally be laid, whatever be the char"acter of the surface, whether level or inclined.”

An interesting and important case involving this question is that of the Carson City Gold and Silver Mining Company v. North Star Mining Company, tried before Judge James H. Beatty, United States district judge of Idaho, sitting as circuit judge. Figure 15 represents the properties in controversy and the underground workings of the North Star mine in horizontal projection.

The line C D traversing the center of the North Star surface was the line connecting the collar of the main working shaft, the mouth of the Larimer incline, the East Star shaft, all sunk on the vein, and a shallow vertical shaft at D. The course of the vein to the west was interrupted at the point C by the occurrence of a "crossing," or a zone of fractured country rock, into which the vein, as far as developed, was not shown to have penetrated. The vein was located in 1851, and had been worked by the North Star Company and its predecessors, with casual interruptions, ever since. The plaintiff in the case, owning the Irish-American ground, contended that the true course of the vein was southeasterly from the point C and across the

side line 12, presenting a case, according to its contention, wherein the North Star Company was denied any extralateral right. The course of many of the deeper levels appeared to sustain its contention as to the longitudinal direction of the vein. The court, however, declined to accept the underground workings as determining the true course of the apex, announcing its views as follows:

"The workings of a mine made in mining operations, "and not in support of litigation, are generally important "as evidence of any facts which may be legitimately in"ferred from them. The three incline working shafts were "started upon this North Star central line, and are all "shown to follow the ledge on their descent. It is reason"able to presume that they were started upon or near the

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apex of the ledge.

As ledges may in their depths change their course, and as the surface course, or the course of the apex, is to govern the miner's rights, the workings nearest the surface are better guides to the course "of the apex than those far below."

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The "strike" of the vein, for the purpose of guiding the miners in making their location, is, therefore, not the "technical true strike of the engineer, the line which "would be cut by a horizontal plane. Such a requirement "would be in many cases impracticable.""

The true method of determination is found in the rule laid down by the supreme court of the United States in the Flagstaff case, and followed by Judge Beatty in the North Star case, that the workings nearest the surface are better guides to the course of the apex than those far below.

The "strike" once determined, the ascertainment of the direction of the "dip" follows as a mathematical deduction. The true average dip of a vein is always at right angles to the strike."

If the strike is north and south, the dip is either to the east or west. The angle of declination is ascertained by a line drawn in the plane of the vein from the top, or apex, to the lowest workings, at right angles to the strike, and the "dip" may be of any degree between the vertical and horizontal.

Of course, a vein in its course downward does not always maintain a uniform dip,-"faults," "folds,” "horses," and local dislocations occur on the "dip," as well as on the " strike," which do not affect the legal identity or continuity of the vein. But these are matters of minor importance, not affecting the rule for determining "strike," or "dip," of the average vein.

In veins that descend into the earth at slight angles of declination, it is of course difficult, if not impossible, at

1 Carson City G. & S. M. Co. v. North Star M. Co., 73 Fed. 597, 601.

2 Duggan v. Davey, 4 Dak. 110, 143.

3 Gilpin v. Sierra Nevada Cons. M. Co., 2 Idaho, 662.