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HEALTHFULNESS OF ALABAMA.

TOPOGRAPHY, CLIMATE, AND MORTALITY STATISTICS,

BY R. D. WEBB, M. D., BIRMINGHAM, ALA.

In an inquiry into the healthfulness of a given region, there are three factors which require examination.

I. TOPOGRAPHY:

a Surface Features.

b Character of Soils.

c Watersheds and Drainage.

d Flora (amount of vegetable matter.)

II. CLIMATE:

a Temperature.

b Rainfall.

c Atmospheric Moisture.

III.-MORTALITY STATISTICS.

O study properly the topography of a region which is largely influenced by the character of its geological formations, we must look at the geology of the region under examination; not so much in the detail of its separate rocks and strata as in the manner in which these geological characteristics were impressed upon it.

In order to do this intelligibly in regard to Alabama, it will be necessary to give, briefly, an account of the geological eras through which it has passed in taking its present features.

Long years ago, Alabama, with the adjoining parts of Tennessee, Mississippi, and Louisiana, was a gulf, or arm of the sea.

At that time what is now the Gulf of Mexico, had its litteral line as far north as Cairo, Illinois, and the mouth of the Mississippi River was probably at that point. This is evident to the most casual observations of the uninitiated in geological science, as the marine shells and fossil casts, everywhere found over this region, testify.

It is generally admitted that our planet was at one time a molten mass, "without form and void," which, in lapse of time, has gradually cooled, forming a crust or shell, enclosing the still semi-molten internal mass. As this cooling proceeded, the globe became smaller, and in places the crust fell in and took a lower level. Into these lower places the waters were collected, forming oceans, seas, and lakes. This is well described in Genesis i, 9: "Let the waters under the heaven be gathered together into one place, and let the dry land appear."

This was the era in which, as stated above, Alabama was covered by an arm of the sea. The latter part of this era is known to geologists as the carboniferous period, when the earth was covered with dense forests, which grew luxuriantly in the moist, carboniferous air, and the marshy lands were filled with cold-blooded reptiles of huge size, which could breathe this carboniferous air. In this condition the earth remained for untold years, during which time the stratified rocks were deposited at the bottom of the seas, and vast accumulations of vegetable debris (coal measures) were collected in the lakes and lagoons which

abounded at that time.

At the close of this carboniferous period, what is known as the Appalachian revolution occurred; by which the great Appalachian chain of mountains (Alleghany, Blue Ridge, and Cumberland ranges) was elevated above the surface of the water. The extension of this chain into Alabama is seen in Lookout, Red and Sand Mountains. It enters the State at its northeast corner, and runs in a southwest direction to Talladega, Centreville, and Jonesboro.

By this geological revolution the face of the country entirely changed, and the shore line of this arm of the sea rolled southward to the northern border of the cretaceous formation, on a line passing east and west through the State from near

Columbus (Lat. 32° 25') on the Georgia line, by Wetumpka and Centreville to Tuscaloosa, and thence veering northwest through Pickens and Lamar counties, and leaving the State on the west near the thirty-fourth parallel of latitude. By this movement all that portion of the State north of this line was elevated to an average of 500 to 800 feet, and in some places as high as 2,500 feet above the sea level.

The central axis of the upheaval was in a southwestern direction, entering the State near its northeast corner and extending to Jonesboro. By the folding or crimping together of the different strata of the silurian, devonian, and carboniferous rocks, those clinal and anticlinal axes were formed, which mark the course of the valleys and ridges of this section. The ridges are Lookout, Red, Raccoon, and Sand Mountains; and the valleys are Brown's, on the west (a continuation of Sequatchie Valley in Tennessee), and Coosa Valley, on the east, with the intervening valleys of Jones', Roup's Will's, and Murphree's.

This upheaval, by which the Appalachain chain was elevated, was probably at first sudden, but was afterward continued more gradually, or, at least, periodically, and consumed a long period of years before the Tertiary sea finally receded to its present shoreline of the Gulf of Mexico, leaving as dry land the southern half of the State.

By this gradual upheaval, the cretaceous formation (rotten limestone) was elevated, the strata retaining nearly a horizotal position; and by its disintegration, and mixing with vegetable matter, was formed that undulating plateau of fertile prairie soil, known as the "Black Bet." This is from fifty to sixty miles wide, its northern line entering the State in the northwestern part of Pickens county (Lat. 34°) and extending in a semi-circular direction around the border of the Appalachian elevation, entirely across the State to the Georgia line, near Columbus (Lat. 32° 25').

This elevating process continued, and the Tertiary sea rolled southward until the entire southern part of the State (Tertiary) was raised above the sea level, and the shoreline receded to its present position of the Gulf coast. This seems to have been without any decided axial lines of elevation, the Chunnenuggee

ridge, which extends across the State from east to west, nearly on the parallel 32° 15', being the only exception, and giving the only hills of any importance south of the southern line of the Appalachian elevation.

The receding waters which followed this upheaval, and the glacial avalanche which swept down from the north, covering all the western and middle part of the State with "drift" of pebbles, sand, and clay, collecting in the lower levels or valleys, marked out the channels of the rivers and creeks and left the surface, by their evading action in its present undulating condition.

By these receding waters was also formed the Quartenrary belt of alluvial formation on the Gulf coast. This is so small, only a narrow strip on the Gulf coast and Mobile bay, that it exerts no material influence upon the sanitary condition of the State, and hence will receive no further special notice.

The physical problem here presented is a little complex at first view, but by a little attention to the principles of geology it will be plain enough; and it is the only method by which we can get a comprehensive and correct view of the physical features of the State.

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Corresponding with these geological changes the State is naturally divided into five sections, viz:

1. Level pine lands (Tertiary), in southern part.

2.

Black prairie lands (secondary cretaceous), just north of the pine lands.

3. Red clay lands (metamorphic), in eastern part. Central mountainous (primary and carboniferous).

4.

5. Tennessee basin (sub-carboniferous).

Let us now, more in detail, refer to the most striking features of each of these sections. Commencing on the south we have: 1. The Level Pine Lands, which extend across the State from east to west, and north from the Gulf on the western border 130 miles, and about forty miles in the eastern part, where Florida projects above the line of the Gulf coast.

This entire region is level, or gently undulating, having the character of hilly only where it is encroached upon by the Chunnenuggee ridge referred to above. It is traversed by the Bigbee and Alabama Rivers, forming by their junction fifty miles

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