Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/108

98 four inches in diameter, through which the brine rises and fills the pit.”

I was informed by an old man who assisted in sinking Walker's pit, that they sunk through soil, gravel, red marly clay, blue and white stone, hard rock, and talc, and that they came to the brine at the depth of 50 yards from the surface; that for the first 15 yards they cut out a shaft, about 8 feet square, this they coated with clay, and afterwards lined with planks, to prevent the springs of fresh water, which are found at that depth, from mixing with the brine. At this depth of 15 yards they found the hard rock, and they then bored a hole of about 4 inches in diameter through this hard rock until they came to the brine, which they found at the depth of 35 yards farther; when they came to the brine, the borer suddenly fell 22 inches, thus indicating the depth of it. As soon as the rock was penetrated, the brine rushed rapidly through the hole, the mouth of which the workmen were obliged to stop, until they got out of the pit. When the plug was withdrawn, the brine quickly rose to the surface and overflowed.

§ 6. Although the information contained in the preceding statements is not very precise, yet they convey a general idea of the nature of the rocks sunk through, and it is very probable that they are similar to those exposed at Doder Hill, immediately contiguous to the pits, and which I have already described. We learn, however, with tolerable certainty, that these springs are impregnated from a body of rock salt; and we obtain an additional testimony in support of the observation, that rock salt is invariably accompanied by gypsum. From the rapidity with which the brine rises to the surface,