sufficiently charged with lime, to be redissolved, reabsorbed, and to supply new generations with covering.

Any excess of carbonate of lime in the earth is absorbed in the passage of the water through it; and thus deposits of this kind form chiefly in limestone regions.

In some localities a process similar to the foregoing has caused the formation of large beds of silicious marl, so called. Various species of phytozoa-organisms occupying the border between the animal and the vegetable kingdom, and in spite of many attempts to locate and classify them, not yet definitely assigned to either-possess a shell or skeleton of silica. These accumulate, as in the case of the testacea, and like the calcareous pond marls are both fossil and recent. The beds underlying Richmond, Virginia, are of the former character.

Silicious marl, being a fertilizer only in the sense that fine sand is, namely, a physical amendment, will not be further noticed; as it is now believed that all soils contain sufficient silica to supply the wants of plant life, and only require assistance in rendering it soluble.

Pond marl, from its friability, minute division, and superficial location, is, in districts where it can be had, the cheapest and best of the purely calcareous manures. It may be applied as extracted or in a calcined condition. In some localities large amounts of this marl are manufactured into lime.

The recent calcareous tufa, travertin or calcareous sinter, formed by the precipitation of carbonate of lime direct from its solution in water when exposed to the air, is often called marl. It is, however, a true and pure limestone; and, physically much resembling the pond marl, is for the same reasons a cheap and ready fertilizer.

Few States having, as yet, been throughly surveyed with reference to their agricultural and their geological character and economical resources, statistics are necessarily incomplete, and much fuller for some regions than for others of perhaps equal importance. The object of this article, however, being as inuch to point out deficiencies as to present the results of investigations already undertaken, such information as is accessible will be presented, in the hope that those interested may be induced to communicate more complete and recent information.

If the recent discoveries on the southeastern coast may be taken as an indication of what is to follow, the field of research is indeed an inviting one.

The older calcareous formations of the Atlantic States constitute a belt of considerable breadth, coinciding nearly with the great eastern mountain chain of the continent, and having numerous offshoots and local outcrops, at greater or less distances from the main range. (See map.) In the eastern States the limestones belong to the so-called Azoic, and to the Lower and the Upper Silurian formations; in other words, the earlier geological ages, The limestone of the Upper Silurian enters Maine from New Brunswick on the northeast; while the same together with the Lower Silurian (Trenton) appears in the mountains of Vermont. Extending along the east line of New York, and approaching somewhat near the coast in northern New Jersey, the limestone belt described passes through Western Virginia, North Carolina, and northern Geor gia to its southern limit in northern Alabama.

The newer calcareous rocks and deposits belong either to the Carboniferous, the Cretaceous, or the Tertiary formation. The Carboniferous limestone appears in Pennsylvania, and, lying west of and parallel to the Silurian, is traceable to the same distance southwest, occasionally being found in or east of the tract occupied by the older rocks.

Limestone of the Cretaceous epoch of the States under consideration is found in Georgia only, the formation being represented further north by the greensand marls. These marls in New Jersey, Delaware and Maryland lie next to the Tertiary, but further inland, and outcrop irregularly, but in a general direction easily traced, through the latter, along the whole Atlantic coast.

The Tertiary formation occupies a belt of very gradually increasing width, extending from southern New Jersey to and including Florida, separated from the limestone range by gneiss, slates, and sandstones, over a wide area. In the tertiary are found large and numerous beds of shell-marl and limestone, the latter invariably the result of consolidation and cementation of the former. In these deposits the shells are frequently almost unchanged either in appearance or chemical composi tion.

At many points on the coast is found a still more recent formation, the Quarternary or Post-Pliocene. This is the locality of the South

Carolina phosphates.

Having thus indicated the general topography and geological character of the mineral fertilizers of the Atlantic States, the specific localities in each State will now be noticed.

MAINE.

Maine is well supplied with limestone of good quality, and so distributed through the State as to be readily available. With the exception of the calcareous beds of the Lower Helderberg of northern and of eastern Maine, which, as before mentioned, is continuous with that of New Brunswick, the limestone of Maine is of the azoic age, and of crystalline or saccharoid texture. The largest outcrops of this rock are in the counties of Knox and Waldo, and have long been worked for lime, for many years supplying the greater part of the lime used in the eastern States. The convenience of access to the main quarries, those of Thomaston, and the excellence of the lime there manufactured, very early created a large demand, which still continues.

The beds lying immediately upon the Keag River, Knox County, are strongly dolomitic. The beds of Waldo County are located in its southern part, and have been largely worked. Numerous small outcrops are found in York, Oxford, and Androscoggin; and in Franklin, Somerset, and Kennebec the beds are not only numerous but extensive. In southern Sagadahock several localities of the rock are reported; also in southern Aroostook and Lincoln, and in Penobscot Counties. In Hancock County the rock, so far as examined, seems to be so altered as to be of little economic value.

The Helderberg limestone of northern Aroostook, northern Penob scot, eastern Washington, and central Piscataquis probably underlies a large extent of country, but has not yet been thoroughly examined. This rock has been manufactured into lime to only a limited extent; its product, however, is of good quality. Thorough analyses of the lime-rocks of Maine are not accessible. The percentage of carbonate of lime in a few specimens is as follows:

Comparatively few localities of pond-marl are reported in Maine; but from their distribution, and the geological character of the State, it is probable that many others exist. Near Ambojijis Lake, Piscataquis County, and in Limerick, York County, are large and easily worked deposits, the Limerick marl lying under peat. Beds are reported at several points in Hancock and Washington. In the former county these have a special value from the lack of limestone of good quality. Marl is found in Oxford and Franklin also; though of the Oxford marls one bed at least, that near Brownfield, is purely silicious. Large deposits of pond-marl are suspected to exist in the county of Aroostook; and a few have already been opened, from one of which the marl was obtained of which the following is an analysis:

The limestone of New Hampshire is altogether crystalline, and of the same formation as the older lime-rock of Maine. It has been found and described in the counties of Grafton, Hillsborough, Sullivan, and Coos. Analyses of New Hampshire limestones give results of some economical importance, some specimens yielding sufficient magnesia to indicate a probable value as water-lime; and others, such a proportion of silica as to cause the formation of slag in burning, unless great care is exercised. These remarks apply, of course, to any limestones of similar composition. Limestone from Grafton County.

Pond-marl is reported in Coos County only, but there is every proba bility of its existence elsewhere. A decomposed limestone found near Lyme, Grafton County, is there known as marl.

VERMONT.

As already mentioned, the greater amount of limestone in Vermont is found along or near the line of the Green Mountains; though, in the words of Professor Hitchcock, there is scarcely a town in the State where it does not exist in some form. Generally speaking, west of the mountains the limestones are purely calcareous, while to the east they are often decidedly magnesian. The azoic crystalline limestone appears in Vermont, as in the preceding States, and is widely distributed. It is found in the eastern parts of Franklin and Addison, in Lamoille, western Washington, Rutland, Windham, and Bennington. In Windsor the rock is extensively manufactured into lime.

The limestones of Western Vermont are of the Hudson, Trenton, and socalled Eolian or Taconic groups. It has been recently claimed, however, that the limestones of the Trenton formation and the Eolian are identical. The Eolian supplies the finest marbles of Vermont, and extends through western Bennington, central Rutland and Addison, and western Chittenden, easily reached at most points, and furnishing a strong and pure lime. The Hudson and the Trenton limestones are found in a narrow range along the northern half of the western border of Rutland County, occupying a wide area in western Addison and southwestern Chittenden; then, dipping under the lake, they reappear in Grand Isle and Isle Lamotte, and in the northwestern part of Franklin County. Orange County, Caledonia, and Essex seem to possess no limestone rocks. Through the center of Orleans County, running nearly north and south, lies an isolated ledge of Upper Helderberg limestone, very silicious, as will be seen from its analysis.