On the west bank of the pool at Poolewe, the landing-place both for Letterewe and the Red Smiddy, is a considerable heap of red hematite exactly similar to that found at Furnace, Letterewe. At the same place are many masses of clay ironstone, which include all the varieties found at Letterewe and the Red Smiddy. In the soil in the bank below Poolewe church, where a jetty and storehouse were erected in 1885, there are also large quantities of clayband ironstone, which were not seen by Mr Marr.
Mr Macadam has examined and analysed samples of all these foreign ores. He is unable to draw the same distinction as Mr Marr between the apparent varieties of clayband ironstone, and thinks that they were in all probability from the same place, and that most likely the south of Scotland. He finds that the samples of hematite ore contain metallic iron varying in quantity from 30 to 60 per cent. The samples of clayband ironstone he finds to yield from 6 to 38 per cent. of metallic iron; they also contain a considerable quantity of lime.
Mr Marr thinks that these foreign or imported ores were mixed with local ore. The lime in the clayband ironstone would render it a useful ingredient from its quality of acting as a flux. Mr Marr adds, "The theory of intermixture of local and imported ores receives support from a similar case in Wales which has come under my observation, where somewhat impure ore containing quantities of phosphorus, occurring among the old slaty rocks of North Wales, is carried to South Wales to mix with the carboniferous ores."
For convenience of reference in our next chapter, the several sources from whence iron was obtained for the smelting-furnaces on Loch Maree, and in other parts of Gairloch, may be classed as follows:—
1. Bog iron obtained locally.
2. Red hematite. Same as found in Lancashire and Cumberland, and unquestionably imported thence.
3. Clayband ironstone, possibly in two varieties. This was also imported either from the south of Scotland or elsewhere.