Prof. Shaler's analysis of Cranston coal (1876) is as follows:

The magnetic iron ore deposit at Cumberland, three miles from Woonsocket, and twelve from Providence, is the most valuable in the State. The "Cumberland Iron Hill" is a mass of ore 500 feet long, 150 feet wide, and 104 feet high, and is estimated to contain over a million tons above natural drainage. Probably a very much larger quantity lies below ground. The ore is not rich in iron-it averages 35 per cent.--but it is extremely free from sulphur and phosphorus, the latter element, as lately determined at the Bethlehem Iron Works, being but 0.026 per cent. The Bethlehem analysis gives the iron in one specimen as 30.86 per cent., and in another at 33 per cent., the silica as 25.5 per cent.

Dr. Chilton's analysis is as follows:

and

Such an ore mined by open quarrying with natural drainage, and almost on tidewater, would seem to be of some value for the steel manufacture.

There are also hematite deposits, the largest being at Cranston, five miles from Providence.

The analysis of this ore by Prof. Willis in 1870 is as follows:

The manufacture of iron in Rhode Island is not exactly a new subject, since it commenced in 1703. Many cannon were cast here from these ores for use in the Revolutionary War and in the war of 1812. The charcoal iron manufacture closed in this State in 1834, when anthracite iron began to be introduced. The authorities of the time pronounced the iron of very superior quality. The Cumberland and Cranston ores were mixed in equal quantities.

It has been estimated that pig iron can be produced in this region at less than $16 per ton, which is no doubt true, seeing that ore, coal and limestone are adjacent and easily mined, provided the coal turns out to be a good blast-furnace fuel. I do not learn that experiments have been made in this direction. But whether iron is produced here or not there is already a largely growing development of coal mining, and it seems probable that ore of this quality, so near tidewater, may find a profitable market.

THE MESOZOIC FORMATION IN VIRGINIA.

BY OSWALD J. HEINRICH, MINING ENGINEER.

(Read at the Philadelphia Meeting, February, 1878.)

DURING the last twenty years much has been done to investigate and define the Mesozoic formation of the United States along the Atlantic States, as well as in the Territories. The investigations of Professors Hitchcock, Emmons, Hayden, H. D. Rogers, and those now in progress in connection with the geological surveys of Penn

sylvania and New Jersey, under the various eminent leaders, have given decided answers to many questions formerly existing, and will throw, as they have already done, much light upon the character of this interesting formation. It is much to be regretted that this formation, existing in the State of Virginia, and first defined there nearly forty years ago, by Professor W. B. Rogers, has since received no public attention. This is the more to be regretted, because Professor Rogers pointed out the economical value of some of its deposits. In order to preserve the results of a series of observations and explorations conducted there during the last few years, and furthermore to preserve the almost inaccessible public records of the former investigator, I beg to submit the following remarks to the Institute.

I. GEOGRAPHICAL DISTRIBUTION OF THE MESOZOIC FORMATION IN VIRGINIA, ITS OUTLINES AND AREA.

Probably more than in any other of the Atlantic States, or in the Territories, this formation occurs in Virginia in isolated tracts and patches of greater or less magnitude, some. being of very limited extent. They appear so now, at least, but by observing them upon the map, a former connection between the tracts may be traced out, by considering the lines of bearings, and comparing the geological structures in Virginia amongst themselves, as well as with those extending into the border States, North Carolina and Maryland. It is also indispensable to take into consideration the elevations now presented by the topography of the country (see Map, Plate V).

For a clearer conception of these facts it will be necessary first to define the outlines of the various tracts, and for a guide we will follow the statements in the various annual reports of Professor W. B. Rogers, which, unfortunately, are now almost inaccessible. They may be enumerated as consisting of four divisions or two double ranges, their main axes running very nearly in parallel lines to each other, and also parallel to the main course of the Blue Ridge mountains, with a bearing from S. 30° to 37° W., the ranges being also nearly the same distance from each other. Proceeding from the east to the west, and also from northeast to southwest, in the line of trend for each, we may designate the following divisions, viz. : A., the Eastern; B., the Middle-eastern; C., the Middle-western; D., the Western division; each consisting of numerous tracts.

A. The Eastern Division.

1. Petersburg deposits. Extending from Richmond to Petersburg, Chesterfield County, and further south to Greenville and Brunswick counties.

Its shape, rather irregular in outline, is nearly that of a rightangled triangle, stretching in its western irregular boundary from Richmond to Petersburg in a nearly meridional line, thence in a northeast course, defined by the overlapping rocks of the Tertiary formation, towards City Point, on the south bank of the James River, and from there in a northwest course across the James River about one mile east of the neck at Dutch Gap, thence in a course a little less northwest to Richmond, where it is exposed in the ferruginous sandstones, the lowest stratum in the valley of Shocko Creek. It can also be noticed upon the top of the tableland stretching beyond the city along the James River within two or three miles west of Richmond, in isolated patches, in Henrico County.

Its entire length would be about 33 miles from north to south, and 8 miles from east to west at City Point, comprising an area of about 95 square miles.

2. Further south the formation occurs in Greenville County, west of Hicksford, and also in the adjoining county of Brunswick, east of Lawrenceville. None of these regions have yet been accurately de

fined.

B. The Middle-Eastern Division.

1. Taylorsville deposits. Containing the territory of sandstones and slates, underlying the Tertiary strata about the South Anna River, from the North Anna River to Ashland, Hanover County.

This tract, which is not well defined, is of a somewhat trapezoidal shape. In consequence of the easy decomposition of its constituent rocks, and the difficulty of distinguishing the Mesozoic débris from that of the underlying Eozoic rocks, which are almost identical with the Mesozoic in material, the lines of demarcation are often obliterated.

Beginning at the head of Machump Creek, near the C. and O. R. R., south of Hanover Courthouse, the boundary extends in a nearly westerly direction to the headwaters of Beech Creek, thence in a variously curved northern line to near the mouth of Beaver Creek, at Newfound River, thence in a northeasterly direction to the neighborhood of Chesterfield depot. The tract, comprising nearly all

the area between this boundary and the North Anna River, is about 8 miles wide between the extreme east and west points, and 10 miles long in its northeast and southwest course, and has an area of about 60 square miles. Taylorsville is situated nearly in its centre.

2. The Springfield deposits, or Springfield coal basin, a small isolated basin, near Hungary Station, on the F. and P. R. R. in Henrico County, a short distance south of Chickahominy River.

It is a basin of elliptical shape, and extends southwest to the head waters of Deep Run. It is situated northeast of the main body and east of the northern spur of the next tract, No. 3, but entirely isolated from it by nearly three miles of Eozoic formation. Its length, northeast and southwest of the main axis, is about 2 miles, and its width, about one-fourth of a mile; its area is about 1.6 square miles, The old Deep Run coal mines have been worked in this basin.

3. The Richmond deposits, or Richmond coal basin. This, generally known as the Richmond coal field, is by far the most important of the deposits. It extends from the northern county lines of Goochland and Henrico counties across the James River to the Appomattox River, lying in Powhatan, but mainly in Chesterfield County.

About 11 miles west of Richmond it extends upon both sides of the James, but mainly upon the south. Its shape somewhat resembles the contour of a plum, with its peduncle pointing north, formed by a narrow branch extending northwards from Tuckahoe Creek for about six miles, averaging about one mile in width.

We will commence to trace its boundary at its northern extremity in the northeast corner of Goochland County, above the head waters of Little Tuckahoe Creek at the northern apex of the triangle formed by the "Three-chopped," the Manakin Ferry, and Pounce's Tract, or Westham roads. It here crosses the first-mentioned road, about half a mile east of Little Tuckahoe Creek, intersecting the main Tuckahoe Creek near the Carbon Hill pits, and running almost due meridionally, forms the east boundary of the spur. It now bears southeast, towards the James River, crossing the same a little above the United States Arsenal, turning again in a nearly due meridional course in an irregular line (in consequence of some smaller outlying patches) to the R. and D. R. R. about half a mile east of Coalfield Station, and a little west of Falling Creek, where we come into the neighborhood of the oldest coal mines in the country, the old Black Heath, Etna, and Midlothian. Then continuing nearly in the same direction, and maintaining a course a little east of the road leading from the pits south to the Genito road, and passing through the western part of St. Leger's