Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/316

 the estate of Mr. Cleghorn, about four miles south of St. Andrew's. This bed is found in a piece of swampy ground, at the bottom of a natural hollow, in attempting to drain which the marle was discovered. It is entirely covered by moss, and also rests upon moss, of which a specimen, taken from beneath the marle, accompanies the shells. In the middle of this hollow the marle is five feet thick.

Logie lies in the parish of Kerrymuir, between Glamis and Forfar. The following succession of beds has been discovered on cutting trenches for obtaining the peat mosses. Moss, containing trees, from four to six feet thick; shell marle, from six to seven feet; blue clay; shell marle, nine inches thick; gravel or quick sand, and sometimes a third bed of marle.

These beds of marle are continuous, and extend over many acres; they are thickest in the middle, and become gradually thinner towards the edges of the bogs.

The marle of Logie, as well as that from Fifeshire above described, consists almost entirely of the shells of the Helix putris, such as are the specimens presented: myriads of this species are now found living in the brooks that flow through the bogs of Logie. Living specimens of the Mytilus cygneus, equal in dimensions to those mentioned by Montagu, and occasionally containing fine pearls, are found in the same brooks: of this shell the marle also contains fragments.

Not far from Logie, in the parish of Forfar, are the moss and loch of Resteneth, which about the year 1794 were entirely drained by a cut made into the loch of Rescobie, lying at the distance of half a mile on a lower level. Both the moss and loch contain shell marle: that in the moss is covered to the depth of five or six feet by line black peat, that in the loch not infrequently so. The marle does not lie in a horizontal bed, but shelves from