ciated with red shale. It
is a calcareous rock, apparently formed in part of pebbles cemented
together and, when burned, produces an inferior lime. It is commonly
known as Potomac marble. Of this variegated marble were formed the
beautiful columns in the old Representatives' chamber of the Capitol
at Washington. The soil in which this rock occurs is extremely
productive and valuable.

The exhibition at the World's Fair, at New Orleans, of the following
specimens of Loudoun minerals claimed much interest from visiting
mineraloguists:

1. _Specular Iron Ore_, from near Leesburg, said to be in quantity.
From Professor Fontaine.

2. _Chalcopyrite_, from near Leesburg, said to be a promising vein.
From Professor Fontaine.

The following were contributed by the "Eagle Mining Company," of
Leesburg; F. A. Wise, general manager:

1. _Carbonate of Copper_, from vein 3' wide, developed to 25' deep.
Assays by Oxford Copper Company of New York give 51 per cent of copper
and 27 ounces of silver per ton.

2. _Sulphuret of Copper_, from vein 10" wide, developed to 50' deep.
Assays by Oxford Copper Company of New York give 12-1/2 per cent of
copper.

3. _Iron Ore_, from vein 4' wide and 50' deep. Yields 55 per cent
metallic iron by assay of W. P. Lawver, of U. S. Mint.

4. _Sulphuret of Copper_, from vein developed 50'. Yields 11 per cent
of copper and 1 ounce of silver per ton by assay of W. P. Lawver, U.
S. Mint.

5. _Carbonate of Copper_, red oxide and glance, from vein 3' wide,
developed to 25' deep. Yields 50 per cent metallic copper and 27
ounces silver per ton by assays.

6. _Iron Ore_, from vein 2' to 4' wide, developed 50'. Yield 55 per
cent metallic iron.

7. _Oxide of Copper_, from Carbonate vein, developed 60' on 4' wide
vein; 25' deep.

8. _Sulphuret of Copper_, from vein 8" to 15" wide, developed 50'.

9. _Iron Ore._

10. _Barytes_, heavy spar, vein undeveloped.

11. _Iron Ore_, from 50' level of Eagle Mining Company's shaft.

12. _Marble_, from quarry of "Virginia Marble Company," three miles
east from Middleburg. The deposit has been demonstrated to be of great
extent; the marble has been pronounced of a very superior quality.
Contributed by Major B. P. Noland.

13. _Marble_, from same as above.

14. " " " " "

* * * * *

17. _Copper Ore_, James Pinkham, from Virginia Department of
Agriculture.

In the "_Handbook on the Minerals and Mineral Re