Page:Popular Science Monthly Volume 82.djvu/191

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187
IMMENSE SALT CONCRETIONS

IMMENSE SALT CONCRETIONS
By Professor G. D. HARRIS
CORNELL UNIVERSITY

Crystalline salt masses may be a mile in diameter! Where are they? How were they formed? Who said so? Interrogations like these are sure to be forthcoming from layman, chemist and geologist alike whenever such startling assertions are made.

Salt is a common substance. Its occurrence in the waters of the ocean, as well as those of land-locked, mouthless seas is a matter of common knowledge. Interesting articles too, have been written regarding the immense layers of rock salt within the earth's crust. They have told of the hundreds of years required in excavating the great chambers and galleries in the Austro-Hungarian mines at Hallstadt, Ischl and Weiliczka. Such mines have been the chose-à-voir for travelers in this monarchy for the past two or three centuries. The Stassfurt mines have become known throughout the world for the richness of their potassium deposits. The Salt Mountain of Cordova, Spain, and the Salt Cliff at Bahadur Khel, in the Trand Indus region of India, are among the notable rock-salt occurrences.

All these salt accumulations have been explained (and perhaps properly) by supposing that they represent the residue of evaporated saline waters, waters that occurred in cut-off bays or sounds, receiving but occasionally supplies from the neighboring ocean, scarcely equaling the vapors lost by evaporation.

Of late an entirely new method of accumulation or growth of rock salt masses has been discovered. Here the salt no longer occurs in thin but wide-extended sheets, layers or strata, but in huge lumps, concretions we may say, with vertical and horizontal diameters approximately equal. These are the masses we wish here to bring to the attention of the reader. We do not have to go to Spain or India to see these marvels. They are, so to speak, right at home. They occur encysted in the sands and clays of the later geological formations along our gulf coast, from east Texas to south Alabama inclusive. Not all are immediately along the gulf border, to be sure, but the majority are but a few score miles from this line. All have doubtless a general conception of the low, grassy marsh-lands of southern Louisiana with its intricate system of tidal bayous beset here and there with dark green live oaks giving the appearance of old-time great apple trees in a great meadow, when viewed from a distant vantage ground. Doming up here and there in