by sinking below the glass rock opening, at the south Forked-Deer Diggings, and at Haswell's mine near Mineral Point. In a few instances, near the latter place, considerable quantities of mineral are reported to have been taken from openings in the lower bed near its outcrops.

A remarkable opening in the blue limestone occurs at the Aspen Grove mine (Shook's Prairie, Green Co..) apparently traversing different beds of the rock, and in its character, unlike any other which I have examined. It forms a very wide vertical East and West crevice, with regular walls, occupied by an opening rock, more or less traversed by seams of mineral and iron pyrites, distinct or combined, intersecting the rock in a manner similar to the arrangement noticed in some of the flint openings (p. 50.) The mineral in these seams is composed of small cubes, more or less regular, grouped in sheets or small bunches, and is accompa nied by more or less of crystallized carbonate of lead, often very distinct and regular. This is sometimes in large quantity, but bas appeared to me only subordinate to the sulphuret. The opening is divided towards the west by a large key-rock, running out in a point towards the east, adjoining which the mineral is said to have been most abundant.

The Upper Sandstone, so far as I have been able to ascertain, hast not yet been found to contain mineral either in crevices or openings; but a sheet of zinc ore and iron pyrites at Mineral Point, already referred to (p. 55,) is said to have been traced 2-3 feet into that rock, in the line of a crevice bearing mineral to the base of the blue limestone. Copper ore is also said to have been found in the sandstone at the depth of several feet, in the same vicinity. It is thus not improbable that if the mineral is interrupted in the sandstone, ores of zinc and copper may be found there in its place.*

If the mineral is interrupted in the upper sandstone, it reap

*The Ulster lead mine (N. Y.) is in a bed of sandstone, interposed between two beds of limestone. This fact offers some encouragement to expect that mineral may yet be found in the upper sandstone.

pears in the Lower Magnesian. Numerous instances are stated of the occurrence of mineral in the lower magnesian in Owen's reports (1847, 1852,) and several other localities have been mentioned to me by different individuals, near the Mississippi, and in the country between it and the Kickapoo, north of the Wisconsin. I shall however confine myself here to my own observations. I have not yet had time to explore the country occupied by the lower magnesian to any extent, and have visited no other diggings in that rock, but those in the vicinity of Blue river, known as Oleking's Diggings. These however furnish satisfactory evidencé that the mineral occurs in that rock, in as proper openings, in as large masses, and arranged as regularly as in the upper magnesian. These diggings are in the sides of a ravine, 60-70 feet deep, leading to the Blue river, about three miles west of Franklin vil. lage. The lower magnesian occupies the sides of the ravine nearly to the summit, where it is overlaid by a low bluff of the upper sandstone. About three fourths of the descent below the sandstone is occupied by a steep slope, formed by the softer upper bed of the lower magnesian, below which is another low bluff formed by the harder middle portion of the same rock. Three successive openings, one above the other, appear to occur here in the lower magnesian; one 8-10 feet below the sandstone, anoth-1 er just above the harder middle bed, and a third below the bottom of the ravine, in the latter bed, and at the depth of about 70 feet in the lower magnesian. The openings appeared partly narrow and vertical, partly wide and flat, with appearances of decomposi tion and stain in the rock, deposits of clay and ochre, and arrangements of the mineral, similar to those in the upper magnesian.') Flint, such as is peculiar to the lower magnesian, is found in the openings, and is connected with the mineral in the same manner as has been noticed in the flint openings in the upper magnesian. The mineral in these openings generally appeared in more or less detached masses (chunk mineral,) often very large, weighing more than 100 lbs; a few even more than 500 lbs.* It was what is *One mass was reported to have been found weighing 3000 lbs.

called pure mineral, free from iron and zinc ores, and strongly resembled that found in the upper vertical openings in the upper magnesian. After examining this locality, I could not doubt that the lower magnesian is a good mineral-bearing rock.

I have thus been able to trace the mineral in a series of crevices and openings from the summit of the upper magnesian to the depth of 60-70 feet in the lower magnesian, and have found all the different beds of limestone good mineral-bearing rocks, each with one or more openings, besides vertical or pitching sheets or veins. The small depth to which mining has been extended does not allow one to trace the mineral through the whole of the extent downward in any one instance, but wherever circumstances permit of examination, the order of succession in the openings is found to be regular, and in multiplied instances vertical crevices and veins have been found passing down from one opening to another. It is then probable that the series is generally continued through the whole downward extent indicated, subject only to such interruptions as are more or less common in all veins. The arrangement appears most analogous to that of the lead mines in the North of England, where the veins traverse different beds of limestone, separated by beds of other rock (sandstone or grit, shale, and toadstone or amygdaloid,) but the mineral is chiefly confined to the limestone, the other beds being generally considered barren, and where there is a similar combination of vertical crevices and veins with more or less extensive flats, corresponding to the flat sheets and openings in the mineral district.

In resuming the statements in relation to the openings in the different strata, it will be seen that at least seven well ascertained openings, not reckoning their subdivisions, have been found in the upper magnesian and blue limestone, namely, two in the upper bed, and one in each of the two lower beds of the former, and one in each of the beds of the latter. The lower magnesian apparently presents three in the instance above specified: two in its upper bed (n upper and a lower,) corresponding to the two in the upper bed of the upper magnesian, and one in the lower bed

at that locality, which is apparently the middle bed of the whole. Admitting a third lower bed with its opening, the whole number of openings in the lower magnesian would be four, and in the whole series of mineral-bearing limestones (upper magnesian, blue limestone and lower magnesian,) eleven.

SURFACE ARRANGEMENT.*

In exploring the different diggings, it will soon be evident that there is a great degree of order in the surface arrangement. The East and West as well as the North and South ranges will be found combined in groups, the different ranges in which are almost invariably parallel. The East and West ranges are obviously the leading ranges, to which the North and South and quartering ranges are appended, but the two latter, particularly when arranged in groups, play an important part in the arrangement, and either interrupt the East and West ranges, or shift them laterally to a greater or less distance. But groups of North and South ranges are sometimes interrupted and even shifted by a single East and West range. The bearing of the leading ranges, known as the East and West ranges, it has already been stated, is rarely, if ever, due east and west, even deviating from that course as much as 45o in some instances; but this bearing is uniform in each group, and often in an extensive series of groups. In a single group of East and West ranges, it will be generally found that the ranges have a common limit towards the east and west, but this limit is rarely at right angles to the direction of the ranges; each range successively receding so as to throw the limit into a direction more or less oblique to that of the ranges. The whole group of ranges will thus take a rhombic form, and if we begin at the most western point of the group, will bear either north-easterly or south-easterly, according as the ranges recede from that point

*My views in regard to the surface arrangement were first formed soon after I commenced my examinations for the American Mining Company in May, 1853, and were stated in reports communicated to the Company in July and August of that year.

on the north or the south. This is called, by observing miners, the direction of the body or weight of the mineral. A remarkable instance of this occurs in the three large ranges, adjoining the village of Platteville, on the Galena road, (Flynn's, Bevins' and the Rountree range.) The north range (Flynn's) extends farthest west, and terminates towards the east nearly opposite the middle of the next range (Bevins',) which again terminates towards the east nearly opposite the middle of the south (the Rountree) range; the body of mineral thus bearing south-easterly. In this instance, the successive ranges recede much more strongly than is usually the case in such groups. In other instances, such strong recessions take place by groups rather than by single ranges; the particular ranges in each group receding but slightly, while the groups recede in the manner above indicated, or even more strongly. An instance of this kind, where the groups succeed each other so as to overlap the adjoining but about half the length of the ranges, occurs in the body of mineral extending from Vinegar Hill (Ill.) to South Buncomb (Wisc.) near the State line. In this instance, the groups of East and West ranges are limited on one side by groups of North and South sheets, which shift apparently by pairs from the east to the west side of those groups. The bearing is to the north-east, but that of the whole body more oblique than that of any single group.

The bearing of the body of mineral may be either north-eastterly or south-easterly according as the ranges or groups recede to the east on the north or south side of the most western point. In the instance at Platteville, the bearing is south-easterly; in that at Vinegar Hill, north-easterly. In some instances, there is a combination of both, the ranges or groups receding castward from a given point, both on the north and south sides of it. This is apparently the case in the body of mineral at Vinegar Hill, which, from a point not far south of that locality, recedes eastward both on the north and the south; the whole body making a bend or curve at that point from north-west to north-east in proceeding from the south.