Indurated Marle or Marlite
The regular shapes of these stones have occasionally made them an object of inquiry. Many years since some were sent me from Fifeshire under the name of Scotch Coits, and from North Wales under the name of Culm Stones. The figure at the back with holes and a sort of mammillæ was sent me from Newcastle, and was said to be placed edgewise in the soil. Such are found in the bed of a river in Lanarkshire, and are also said to be found in the vicinity of Lough Neagh in Ireland. Rings and fanciful figures Something similar are found at Hopedale, Labrador; the two lower figures, one resembling a bird, and another curved acuminated one, are from thence, and were presented to me by the Rev. Mr. Latrobe: I add them here to show different varieties, which indeed are endless. They appear to be a deposit of Marie as from some mixed Clay and Lime rocks washed with water, sometimes taking one figure, some times another, according to circumstances, which, however, would puzzle the best geologist to discover, like many other of the most simple works of nature. My friend Mr. Oldham has observed some very analogous things, forming at the Dalston clay pits near Hackney. The substance is much the same, but the specimens are more rugged in general. They seem to harden in a different manner from Clay alone, as well as from common Marle, nor will they easily mix with clay for bricks or tiles, nor do they fall to pieces like the marly septaria.
These are not in my knowledge mentioned in any former work.