Imágenes de páginas
PDF
EPUB

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 composition.

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:

79.6 43.6 65.0

Oxford County..................
Androscoggin County...........
Franklin County ....
Somerset County, bighest...
Kennebec County, average ..
Penobscot County, highest......
Piscataquis County, average.........

75.0 89.2 62.0

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 inany others exist. Near Ambejijis Lake, Piscataquis County, and in Limerick, York County, are large and easily worked deposits, the Limerick marl lying under peat. Beds are reported at sereral 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:

[merged small][ocr errors][merged small]

NEW HAMPSHIRE. 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 Graftop, 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.

[ocr errors][merged small][ocr errors][ocr errors][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small]

23.8.

Carbonate of lime..........
Carbonate of magnesia...
Oxide of iron.....
Silicious matter...

56.4

10.8 Traco.

33.0

2.8 25.0

100.2

98.2

Pond-marl is reported in Coos County only, but there is every probability 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.

Thelimestones of Westeru 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 iden. tical. 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.

[merged small][merged small][merged small][ocr errors][ocr errors][merged small][merged small][ocr errors][merged small][ocr errors][merged small]

30.82

Carbonato of lime......
Carbonate of magnesia........
Alumina and oxide of iron.......
Silica..... ...
Water and loss......

cici

02.03 83.5

[merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

In view of this general distribution of calcareous rocks it would naturally be expected that many localities of pond-marl would be found in Vermont, and accordingly we find numerous beds of this fertilizer in a belt of country twenty to thirty-five miles in width, extending through Wind. ham, Windsor, and Orange, along the Connecticut River, and northward through Washington, Caledonia, and Orleans. In the western portion of the State the only deposits reported are on Grand Isle and at Monkton, Addison County. But four analyses of Vermont marls are at hand, but these may safely be taken as representative.

Marl from Grand Isle.

Carbonate of lime...
Carbonate of magnesia...
Silica, and trace of alunina, and oxide of iron
Water and organic matter...

2.6 12.3

100.0

Marl from Orange County, (Williamstown.)

Carbonate of lime.............

..................... Carbonate of magnesia........

............................................ Silica, and trace of alumina, and oxide of iron.......... Water and organic matter....

[ocr errors][ocr errors][ocr errors]

Marl from Caledonia County.

Carbonate of lime.
Carbonate of magnesia....
Silica, and trace of alumina and oxide of iron
Water and organic matter..

1.0

10,5

[merged small][ocr errors][merged small][merged small][merged small][merged small]

The Eolian limestone of Vermont extends ipto western Massachusetts, and, as in the former State, furnishes lime of the best quality and in immense quantities. Its outcrops are confined to Berkshire County, running north and south across the State ; but the crystalline azoic makes its appearance in all the counties of the State, to a greater or less extent, except in the peninsula of Barnstable and its neighboring islands, which are recent.

Limestone from Berkshire County. .

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

Carbonate of lime..
Carbonate of magnesia.......
Oxide of iron...
Silica, alumina,

56.25 31. 56

1.12 11.07

« AnteriorContinuar »