Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/317

 the middle of the loch, where it is eleven feet thick, to the edges of the moss, where it does not exceed in thickness a few inches.

The marle of Resteneth consists of the shells belonging to the Helix putris (Pennant), (peregra Montagu), and the Cardium amnicum (Mont.), both which are now found living in the waters that How through the loch. Neither of these in size much exceed a pea; yet not less than two millions of cubic feet of marle had been dug between the years 1794 and 1807 for agricultural purposes.

Resteneth loch lies about twelve miles distant from the sea at the level of 196 feet above low water mark. It gives rise to a considerable stream, which flows into the sea about thirteen miles east of the loch, after forming in the three first miles of its course the lochs of Rescobie, Balgarvie and Balmodin, in all which shell marle is obtained by dredging with boats; in the loch of Rescobie at the depth of 25 fathoms.

Lord Duncan's loch is situated in the parish of Lundie, eight or nine miles north-west of Dundee. It covers an area of seventy acres, of which fifty have been drained, and from which shell marle is dug, as in that of Resteneth.

In all these places we have the same appearances; the marle always occupying some natural hollow or basin, which either is or has been the site of a pool of water. In Resteneth loch we have