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5. Porphyry, decomposed, sandstone and limestone. Samples as follows: At 231 ft., clayey material, pink, very fine, calcareous.

300 ft., like the above, but coarser, with free quartz and porphyry fragments. 335 ft., clayey material, brick-red color; quartz grains, rounded, with red

clay between; slightly calcareous.

342 ft., grit like that at 153 ft., but not so coarse, slightly calcareous....

5. Porphyry, solid, hard.

Total thickness..

Section XI (No. 11 of Section sheet).
RECORD OF IRON MOUNTAIN DRILL-HOLE NO. 13.

1. Clay..

Altitude of surface is 1065 feet A. T.

112

.......

12

354

2. Sandstone. Samples at various depths are as follows:

At 24 ft., pinkish-gray; fine-grained; strongly effervescent; grains of quartz and
porphyry.

66 65 ft., a coarse grit with sub-angular quartz and decomposed porphyry.
95 ft., a grit, less coarse than the last.

FT.

17

66

130 ft., a grit like the last, but containing more rounded quartz grains. 3. Limestone (?); at a depth of 140 feet, a sample is of a light gray color, finegrained, and contains more quartz than lime

120

......

47

4. Sandstone; a sample at 190 feet is a fine grit with sub-angular quartz grains of reddish-gray color......

28

5. Porphyry decomposed ("wash") and grit. Samples are as follows: At 337 ft., a coarse grit of quartz and decomposed porphyry, calcareous. "240 ft., like the last, but coarser.

246 ft., like the last.

255 ft., like that at 227 ft.

278 ft., "wash," consisting of coarse fragments of porphyry and some

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3. Sandstone. Samples at various depths are as follows:

At 28 ft., pink, quartz grains, sub-angular and rounded, of medium size, some porphyry.

43 ft., light gray, finer, more homogeneous than the last.

80

10

1

303

FT.

14

12

At 721 ft, a calcareous sandstone or arenaceous limestone; pinkish gray, fine

grained.

66 77 ft., like last, but coarser.

"SO ft., "sand and limestone," grayish-red, very little lime.

"86 ft., a grit of quartz and porphyry fragments.

88 ft., like the last, but finer, sub-angular quartz grains.

96 ft.. like the last, but finer.

106 ft., sandstone, soft, with fragments of porphyry.

4. Grit and decomposed porphyry. Samples:

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At 114 ft., dark drab, with large particles of porphyry and some quartz grains; slightly calcareous.

128 ft., like the last.

132 ft., decomposed porphyry, strongly calcareous on surface of fragments. 139 ft., porphyry, slightly decomposed, calcareous...

5. Porphyry, hard. Sample at 147 feet strongly calcareous.

Total thickness...

33

9

148

Section XIII.

RECORD OF IRON MOUNTAIN DRILL-HOLE NO. 20 (at sandstone quarry).

Altitude at surface is 1037 feet A. T.

1. Limestone, light gray color; quartz grain subangular.

FT.

4

2. Sandstone, light yellow, gray and white, effervescent, almost a limestone.. 3. Sandstone, pink; not calcareous; grains sub-angular....

19

6

4. Sandstone, reddish gray; quartz grains sharp or sub-angular, with crystalline faces; mixed with porphyry grains; not calcareous, or slightly so

40

5. Sandstone, pinkish gray; fine-grained, quartz angular, grains of pyrite and some porphyry; strongly calcareous....

6

6. Sandstone, dull pink, angular quartz grains and fine porphyry grains; non-cal

careous

11

Total thickness.

86

A study of these sections reveals a great variability in the character of the rocks, and there is a corresponding and consequent difficulty in the correlation of the different members. As is noted, some of the strata denominated as sandstones are highly calcareous, and might, with well-nigh equal propriety, be termed limestones; with the arenaceous limestones a similar observation is true. An attempt at a correlation is expressed in the following diagram; but it is, confessedly, only approximate. Much of this variability is doubtless due to the marginal position of the sections, situated as they are near the old Iron mountain shore line, where eddies and currents undoubtedly existed in the Paleczoic sea, producing rapid local changes in the strata. But, though we may expect to find less variation away from such mar

gins, the sections here harmonize with those at other points in indicating a general inconstancy. They further support the general rule that arenaceous layers or grits are the lowest lying members of the thick deposits, and that such generally intervene between the body of the magnesian limestone and the porphyry or granite floor.

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Fig. 7. Block map illustrating variability in succession of Paleozoic strata, as revealed by drilling at Iron Mountain.

Exposures from which long, continuous sections can be made, do not exist in the vicinity of Iron Mountain, though scattered out-crops are very frequent. Thus, opposite the railway, a quarter of a mile west, is a limestone quarry, exposing magnesian limestone of typical character. The face is 10 or 15 feet high. The rock is coarse and crystalline, characteristically filled with small cavities, lined with dolomite crystals, but containing also large porphyritic illy formed calcite crystals in the mass of the rock. It is of a yellowish color. Analysis No. 5 of page 28 is of rock from here. This limestone is considered to overlie the sandstones exposed in Little mountain, and to be the equivalent of the upper limestone beds noted in Sections IV, V, VI, VII and IX.

Less than half a mile north of here is the sandstone quarry at which the drill hole of section XIII was sunk. The rock exposed is coarse and gritty with numerous small particles of decomposed porphyry. It undoubtedly underlies the limestones to the east, in which direction it dips; in fact, the axis of a gentle anticline, trending east and west, appears at this point.

Less than a mile north of the depot, where the wagon road crosses the railway, a yellowish sandstone crops out in conspicuous ledges. It dips slightly to the west. It must be close to the solid porphyry of Iron mountain to the east, and it contains many fine particles of decomposed porphyry. Similar rock is exposed farther along this road, at the south end of the hill immediately west of the railway at this point. It is also exposed, about 10 feet thick, shaly in part, between the two porphyry hills, just north of the last point, at the middle of the western line of section 30, township 35 N., 4 E. It also occurs and has been quarried about a mile farther north, near the middle of section 19 of the same township. The rock here is very coarsely grained and friable, of a whitish-gray color, with large grains of quartz, and also fragments of light-colored porphyry. The stratum quarried from is about three feet thick, and lies in a nearly horizontal position. Many of the quartz grains of this and other exposures described show crys. tal faces which are evidently the results of secondary growth.

Belleview Valley.-West of Iron mountain is Buford mountain, and beyond this again is what is known as Belleview valley. This is the largest area of Paleozoic rocks within the limits of the sheet. Numerous exposures of limestone and sandstone are encountered. None of these are, however, of great vertical extent, and opportunities for the construction of long, continuous sections are absent. A series of drillholes have been put down in this valley, but the writer was unable to obtain records of these for incorporation in this report.

About three-fourths of a mile east of the village of Belleview, the following section is exposed at the fork of the road shown on the map:

Section XIV.

OUT-CROP AT ROAD AND CREEK CROSSING, & mile E. of Belleview.

Altitude of surface is about 980 feet A.T.

1. Limestone, white, crystalline, thinly bedded, with calcite crystals.. 2. Sandstone, gray, soft, with numerous fine grains of porphyry..

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Considering the distance of this section from an Archean area, the rocks exposed must be at least several hundred feet above the base of the Paleozoic column here. The included sandstone beds must hence

be classed among the thin and non-persistent layers of the upper portions of the rock column, which have been recognized elsewhere.

Thence northward, down Cedar creek, out-crops of limestone are frequent. At the ford, three miles due north of Belleview, on the south bank, a bed of sandstone rises from about the level of the creek to a height of from 15 to 20 feet; above this about 15 feet of limestone is exposed.

South of Belleview and along the road thence to Graniteville is a great area of chert-covered "Flint-hills," which rise to an altitude of nearly 1600 hundred feet, or nearly 600 feet above the valley. They are covered with chert in nodular masses, and of irregular size.

Graniteville.-About a mile southwest of Graniteville,approximately at the point designated on the map, a drill-hole was put down to a depth of 350 feet, known as the Sweeney drill-hole. A complete record of this hole could not be obtained, but samples, kindly furnished by Mr. Thos. Beard, of Ironton, were examined by the writer with the following results:

Section XV (No. 12 of Section sheet).

NOTES OF SWEENEY DRILL-HOLE NEAR GRANITEVILLE (S. E. 1, S. W. 1, Sec. 15, Twp. 34 N., 4 E.

Altitude of surface is about 1300 feet A. T.

FT.

1. Limestone, magnesian with calcite crystals; coarse, crystalline of open texture, at 108 2. Limestone, finer grained with silica..... 3. Limestone, finer grained with silica.... 4. Limestone, like (1), but quartzose..

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14. Limestone, dolomitic, dark gray, fine-grained.. 15. Grit, with porphyry fragments..

16. Limestone, magnesian, coarse, open..

17. Sandstone, fine-grained, light drab
18. Grit, pink, with porphyry fragments.
19. Grit, coarser, with porphyry fragments..
20. Porphyry conglomerate..

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