Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1871 Excerpt:...of feldspar and there it graduates into a kind of stratified porphyry. In the valley between Grand-fond and the eastern coast of the island occur a great number of interesting varieties of breccias and conglomerates. They have K. Vet. AWad. Handl. B. 9. N:o 12 4 often been strongly altered, probably by infiltration of water containing silex in a state of solution. In some places, as near the mines, I have seen specimens of breccia transformed to quartz with many small spots of pyrite, but still with the structure of breccia perfectly well conserved. The hills around Grand-fond consist chiefly of chert, which has originally been a breccia. North of Grand-fond some metalliferous veins are found, containing lead-minerals, and some copper. The vein-stone is quartz containing some epidote, heavy spar, pyrite, hematite etc. The vein strikes from North to South and has been worked lately. The mines were opened in June 1868 and on my visit to the island in Febr. 1869 there was a mine of the depth of 14 fathoms. The quantity of lead-ore extracted from this mine was 4 tons. Another mine, the working of which had been commenced in Oct. 1868, was at the time of my visit 9 fathoms in depth, and about 3 tons of ore had been found there. The lead-ore is said to contain 10 ounces of silver in the ton. In the point west of Grand-fond there is also a vein, excavated in the seacliffs to a cave, whose walls, continually moistened by spray from the breaking sea, are covered by gypsum and in some spots by a white soluble salt, containing a compound of sulphate of sodium and alumina. I found there, also, a new compound of sulphate of sodium with basic sulphate of peroxide of iron for which I propose the name of Bartholomite. It occurs in yellow masses and is distinctly crystaline...