42 KENTUCKY
connecting with the Mississippi system, and furnishing a most advantageous means of cheap transport for coal, timber, &c. A system of river improvement, begun by the State some years ago, by which the Green and Barren rivers from Bowling Green downwards, and also the lower portion of the Kentucky river, were made continuously navigable, is being prosecuted still further by the United States Government. It is now possible to float down logs, rafts, flat boats, &c., from almost the fountain heads of the rivers.
Climate. – The climate is very mild and salubrious. The mean
annual temperature ranges in different parts of the State from 50°
to 55° Fahr. The extreme range is less than in the States north and
west. The lowest record at the United States Signal Service Station
during the exceptionally cold months of December 1880 and Janu
ary 1881 was -8°. During the very hot summer of 1881 the maxi
mum temperature was greater as far north as Chicago than in Ken
tucky. Cattle remain upon pasture during the entire winter, with
but little additional food, and there is seldom a day, winter or sum
mer, when a man may not perform a full day s work in the open air.
The healthfulness of the climate is attested by the low death-rate
and by the strength and vigour of the population. The tabulated
measurements of the United States volunteers during the civil war
show that the soldiers born in Kentucky and Tennessee exceeded all
others in height, weight, circumference of head, circumference of
chest, and ratio of weight to stature. The speed and endurance of
the Kentucky horse, and the superior development of all kinds of
domestic animals, are well known. The annual rainfall ranges in
various parts of the State from 45 to 50 inches, and is probably
still higher in the Cumberland Mountains.
Geology. – With the exception of the more recent formations in the portion of the State west of the Tennessee river and along the valleys of some of the streams, Kentucky is composed entirely of Palaeozoic strata, having present all of the various groups found in the Ohio valley, from the calciferous sandrock (3a of Dana's Table of Formations) to and including the carboniferous. The united thickness of the various groups is not great in Kentucky, – probably not aggregating over 5000 feet. The entire State is included within the area of the great Appalachian uplift. In the south-east the disturbance is greater, the strata often being inclined at a high angle, the successive undulations gradually diminishing toward the north-west. This disturbance in the south-east is emphasized by the Great Pine Mountain fault, extending parallel to the axis of the Appalachian uplift, entirely through the south-eastern portion of the State, and bringing to the surface in the Coal-measures rocks as low as the Clinton group of the Upper Silurian. The axis of the greatest geological elevation in the State is parallel to the above, and passes in a north-easterly and south-westerly direction through the counties of Montgomery, Clark, Madison, Garrard, Jessamine, and Boyle, shown on the map by the deflexion of the Kentucky river from its general course towards the Ohio river. This uplift brings to the surface the lowest rocks exposed in the State, – the "bird's eye" limestone of the Trenton (4a of Dana), and the dolomite, known as "Kentucky river marble," including what is probably the equivalent of the calciferous sandrock of the New York section. These lower rocks of the Kentucky section form a triangular area having its depressed apex north-west of Frankfort, and its elevated base in the counties named above. Through these formations, having a thickness of over 400 feet, the picturesque gorge of the Kentucky river has been cut. Next in ascending order we have 150 feet of blue, fossiliferous limestone, containing characteristic forms of the Trenton of New York, and 800 feet of limestone and shales containing the fossils of the Hudson river or Cincinnati groups (4c of Dana). These groups make up the well-known "Blue Grass" region of Kentucky, celebrated for fertility of soil, high agricultural development, and superiority of the horses and other domestic animals produced. The soils of the most fertile portion of this region are derived from the 150 feet immediately above the bird's eye limestone. These rocks are very rich in phosphate of lime, and with careful tillage and proper rotation of crops the lauds are not exhausted by cultivation. The blue limestones of central Kentucky are very prolific in fossil forms.
Surrounding this central region are the rocks of the Upper Silur ian, averaging in thickness about 100 feet. East of Louisville this formation is about 25 miles wide, and in eastern central Kentucky about 10 miles wide, decreasing in thickness and in superficial extent toward the south-western portion. The rocks are mostly magnesian limestone rich in fossil forms, of which the most charac teristic are the beautiful chain corals. The soils of this formation are less fertile than those derived from the blue shell limestone and marly shales of the Lower Silurian. Above the latter formation, and forming the outer portion of the semicircle or irregular triangle extending around the great central uplift, are the corniferous lime stones of the Devonian (9c of Dana). The principal exposure is
seen at the falls of the Ohio below Louisville, at low water pre senting probably the most beautiful and extensive natural cabinet of corals in the world,- a reef of corals, perfectly preserved in minutest structure, and of exquisite beauty. The soils derived from these rocks are of almost equal fertility to the best soils of the blue limestone, and. the topography is equally pleasing to the eye. The next formation in order is the black shale (10c of Dana) of the Devonian, with a thickness of about 150 feet in the north-east, and decreasing gradually to the south and west. This formation is peculiar from the high percentage of petroleum contained in the shale. Before the discovery of oil-wells oil was distilled from these shales, and the oil in the productive wells of Kentucky is derived from the same source. Where this shale determines the topography the lands are generally flat, often with insufficient drainage, and are not so productive as analyses would seem to warrant. Doubt less underdrawing will increase the yield.
The Subcarboniferous rocks, consisting of the several groups identified by fossil remains with the Waverly, Keokuk, Warsaw, St Louis, and Chester groups (13, 13b, and 13c of Dana), com posed of sandstones, shales, and limestones, with a total thickness of over 1000 feet, cannot here be described in detail. Muldrows Hill, representing the retreating escarpment of formations which formerly extended over the central Blue Grass region, is composed of these rocks, capped at Big Hill in Madison county with the carboniferous conglomerate. The Subcarboniferous limestone region of western and southern Kentucky, drained by the Green and Cumberland rivers, is characterized for the most part by an excellent soil, well adapted to the growth of Indian corn, wheat, barley, and other cereals, pro ducing a very fine quality of tobacco, and certain grasses in great perfection. This formation is noted for the numerous caverns of large size and great beauty, the best known being the" celebrated Mammoth Cave in Edmonson county, which is the largest known cavern in the world. Here many miles of subterranean passages have been excavated by the eroding action of water charged with carbonic acid, assisted in places by the action of the atmosphere. The caverns are beautified by columns and stalagmites formed by the deposition of carbonate of lime from the percolating waters, and by exfoliation of sulphate of lime, taking the form of flowers, rosettes, and other shapes, rendered more beautiful by their power of reflec ting light. See MAMMOTH CAVE.
The detailed survey of the Carboniferous strata of Kentucky is not yet completed, but enough is known to justify the assertion that the total area in the State is over 14,000 square miles, 10,000 square miles of the Appalachian coal-field and 4000 square miles of the western or Illinois coal-field. In the eastern field two work able coals are found below and twelve above the carboniferous conglomerate. The eastern field is remarkable for the thickness of some of the coal strata and the purity of coals, for the large area of excellent cannel coals, and for the ease with which the coals may be mined, being mostly elevated above the drainage level. The thickest portion of the measures is in the synclinal trough between the Pine and Cumberland Mountains, there being a vertical thickness of over 2200 feet of Coal-measure rocks above the drainage level. In the south-eastern portion of the eastern field an excellent coking coal has been traced over a wide area. This coal ranges from 4 feet to 8 feet in thickness, can be mined cheaply, and has a very low percentage of ash and sulphur. The western coal-field is a broad synclinal, its axis almost parallel to the general direction of Green river, crossed by undulations the axes of which extend from north east to south-west. No workable coal has been opened below the con glomerate, which is thinner than in eastern Kentucky. Twelve coals are present in the measures above the conglomerate. Some of these coals are of excellent quality, although the percentage of sulphur is larger than in the best of the eastern Kentucky coals. The soils of the Coal-measures are variable in quality. Some of the most pro ductive lands in the State are in the western coal-field. In the eastern field are very fertile valleys, and the uplands in the Cum berland valley are quite productive. Even the poorest of the Coal- measure soils are well adapted to certain grasses and fruits, and will yield good returns from intelligent culture.
There only remain to be noticed the Quaternary strata. The region west of the Tennessee river, and the level plains bordering the principal rivers and above high-water level, are composed of a homogeneous buff-coloured silicious loam known as the "bluff" or loess formation (20b of Dana). This is, with the exception of the alluvial "bottoms" along the rivers, the most recent forma tion in Kentucky. The deposit has a thickness of from 40 to 50 feet. Owing partly to the presence of numerous land and freshwater shells (Helix, Cyclostoma, Pupa, Cyclas, &c.), this for mation is highly calcareous, giving from an average sample 9 6 per cent, of lime, and the soils are of marked fertility. This bluff loam rests upon a coarse gravel, varying in thickness from a few inches to 30 feet, composed mainly of water-worn pebbles from the carboniferous conglomerate, and slightly water-worn angular pebbles of chert and hornstone from the lower Subcarboniferous and corniferous groups, and coarse angular sand. Intermingled throughout are silicified fragments of many of the Palseozoic fossils
