In the number of your journal for October, 1860, I read with great interest a paper by Dr. Watson “On the Metalliferous Saddles of Derbyshire and Staffordshire.” The Doctor says that, though well known to the miners, he believes these saddles have not hitherto been described by any geologist. If he will refer to the Journal of the Geol. Soc., 1857, p. 233, he will find a paper “On the Mines of Namaqualand,” in which I think he will recognise a description of these deposits under the name of “metallic axes.” With such modifications as the difference in the strata and their metallic contents requires, his description would nearly apply to what I said.

The strata in which my axes occur are gneiss and gneiss-granite with occasional beds of magnesian and micaceous rock at Springbok Vontein and Concordia, and micaceous and calcareous rock, with gneiss at Kodas. The saddles (a better name than mine) in all the productive mines were folds in the strata, with fissures of various sizes and directions intersecting them. The one was in some cases more abundant in the planes corresponding to the original bedding of the rock: this was strikingly the case at Concordia, where the main dip was north and the disturbed one south—the strike of the rocks being nearly east and west. (Sec. 1 and 2).