Occasionally, however, is found the layer of blue rock resting immediately on the layer of phosphatic limestone, and where this is the case numerous faults and dips occur, showing a similar structure to the Mt. Pleasant formation typified.
Again, in the central basin or brown rock region, the top erosion first disintegrated and then partially took off the upper layers of shale or flint, sometimes entirely, sometimes leaving it from one to forty feet thick, which accounts for the varying overburden.
In some places the limestone layers were entirely soluble or reduced to clay and some acid condition of soil water dissolved the upper layers of phosphate and redeposited it in the boulder and stalagmite forms of the “white rock” found in Perry and Decatur counties and near Godwin, in Maury County, and the “boulder rock” found everywhere to greater or less extent but in especially heavy deposits near Nashville on the McGavock Place. These latter redeposit varieties vary in analysis from 50 per cent to as high as 90 per cent phosphate, and are uncertain as far as the general variety goes, though individual deposits varying in extent from one to twenty or thirty acres, are found of very uniform quality.
The first phosphate rock discovered in Tennessee was the kidney formation that almost always attends the blue rock and black shale deposit. The eminent physician, naturalist, botanist and geologist, Dr. Gattinger, of Nashville, of revered and beloved memory, was first to recognize these as phosphate rock, but being much more interested in determining the family and pedigree of some new beetle or plant than in the commercial aspect of any mineral proposition, he never gave his discovery to the world, and only by his casual mention of the fact one day to Will Shirley and Maj. W. J. Whitthorne, of Columbia, are we able to give him credit for the knowledge. Dr. Safford, in his “Geology of Tennessee,” describes in detail both the blue and brown rocks geologically, referring to the blue rock as a blue fossiliferous limestone nearly always occurring under the Devonian shale; but no chemical investigations being provided for, he did not find out that it was a phosphate rock. Major Whitthorne and Mr. Shirley kept up a systematic hunt for a deposit of commercial value and finally the former located one on upper Swan Creek simultaneously with the discovery made lower down the same creek by Messrs. Bates and Childs. These latter gentlemen were insistent that the black shale, commonly called slate rock, so abundant in the highland rim country, was a form of, or indicative of the proximity of, coal, and at regularly recurring intervals they would send in particularly promising looking samples to Professor Wharton, of Nashville, for analysis. One day they dropped into their bag of samples a piece of blue rock which they informed Professor Wharton was nearly always present under the “slate,” and seemed to be a “bloom.” What was their astonishment to receive from Professor Wharton the report that their coal was still worthless, but that their bloom was phosphate rock, analyzing over 70 per cent. This was in December, 1893, and like the news of William Tell in Switzerland, of old, “From hill to hill the summons flew,” and the whole country went phosphate and option mad.
Lack of transportation and timidity of capital, coupled with the large amount of territory occupied by the deposit and the numerous parties holding properties caused the development to be spasmodic and comparatively small and scattered, and in consequence the price soon fell from $4.25 per ton f. o. b. Aetna, which was the first sale, made by the old Southwestern Phosphate Co., to $2.25 per ton, which was the price at which blue rock guaranteed 65 per cent was sold in 1896, being just a small margin over the cost of production and hauling to the railroad.
In January, 1896, at a time when negotiations were on foot for the sale of a large tract of blue rock land on Swan Creek, Mr. S. Q. Weatherly, former county judge, and prior to that county surveyor of Lewis County, while on a trip to Mt. Pleasant, noticed the peculiar brown rock in the ditch at the roadside on the W. S. Jennings’ farm west of Mt. Pleasant, and being interested in minerals, picked up a piece of it. Noticing the analagous appearance to the weathered blue rock, which is generally brown on the surface, he dropped it in his buggy. On his return to Swan Creek, he showed it to Mr. Harry Arnold and Col. D. B. Cooper, who were interested in the negotiations above mentioned. These gentlemen had it analyzed and finding it to be 75 per cent phosphate rock, induced Mr. Weatherly to say nothing about it until after their deal was consummated. Associated with these gentlemen was also Mr. W. J. Webster, and during the time from January to July, 1896, when the negotiations for the sale of the blue rock properties were finally closed, they ascertained partially the extent of the Mt. Pleasant brown rock field.
When their “big trade” was made they formed the firm of H. I. Arnold & Co., bought two and one-half acres of land from Mr. Mumford Smith, ostensibly for a calf lot for Mt. Pleasant’s present genial mayor, Mr. W. D. Cooper, leased at a royalty of ten cents per ton a few acres from Mr. Cooper and a few from a darky named Tom Smith, got an option from Mrs. M. G. Frierson on the present Columbian & Blue Grass Hills, and commenced mining rock and putting it on the cars at a cost of about eighty-five cents per ton. This rock, without preparation, ran 75 per cent instead of 65 per cent, but whereas the blue rock had never run higher than 3 per cent I. & A., this rock ran, in the state they shipped it, from 4½ to 6 per cent I. & A.
Of course the manufacturers had bought blue rock for $2.25, and knew they were getting it at very nearly the cost of production, and when they saw the “snap” the miner had, they took the stick this excess of I. & A. gave them and proceeded to beat the price down with it until $1.25 and eventually $1.00 per ton were common prices.
Capitalists were rendered more timid than ever before, and even astute phosphate man that he was Col. D. B. Cooper threw up both hands and quit. He said, “Boys, if that is phosphate, the whole basin of Middle Tennessee is full of it, and it will never be worth mining, as every farmer will pick it up off the ground and haul it to the railroad.”
Mr. John S. O’Neal, in a paper presented to the Engineering Association of the South, as late as 1897, said, “the owner of a bed of phosphate rock, is not as well off as the owner of a sand bank, given the same proximity to market.”