Some of the claims at the west of the mine never paid the expense of working at the surface, nor even in the yellow ground below, and remain absolutely worthless to this day, although the blue ground has been reached, worked, and tested. About five claims in the very centre of the mine were proverbially poor, vast quantities of erratic boulders being mixed up with, and in some cases almost displacing, the yellow and blue ground. Some of these fragments of rock were of immense size, weighing thousands of tons, and at the same time were so solid that they had to be blasted to pieces. They consisted for the most part of dark and light colored shales, whinstone or basaltic boulders, and large masses of fine-grained micaceous sandstone, containing fragments of coal and remains of a fossil reptile. Much lignite in large stems and branches was also found amongst the boulders and in the blue. When this floating reef was removed, many feet of unprofitable blue had also to be removed before payable ground was reached, but when all the poor ground was taken away, the junction of which with the richer ground was very perceptible by a change of color, the remaining blue did not differ in average return of diamonds from the rich claims surrounding it. Several remarkable detached boulders were found. One in No. 3 road south, of such a large size that it covered the two claims of a well-known digger named Olsen, Nos. 136 and 166. It was a pudding-stone, its chief constituent being grayish white crystals and fragments of feldspar, transparent and translucent, concreted together with carbonate of lime. This “erratic” contained also nodules of quartz, crystals of iron pyrites, and many small cavities filled with diamondiferous soil of a light brownish gray color. Again in Nos. 8 and 9 roads south, there was an isolated basaltic boulder, nearly round, of gigantic proportions. It almost filled up claims 432 and 433 in road No. 8, and claims 462 and 463 in road No. 9, and measured in diameter 70 feet, 35 feet in the yellow ground and the same in the blue below. It was much decomposed, and large flakes or layers frequently fell away into neighboring claims, causing many lawsuits. The claim-holders burrowed round this piece of rock as long as they possibly could, but at last they had to face the expense of breaking it up and removing it. The upper portion of this stone in the yellow ground had a yellow, and the lower portion in the blue a blue tint, showing that the same cause which affected the coloring of the diamondiferous ground also affected the imbedded “erratic.” The floating reef proper in the Kimberley mine extended from the southeast to the northwest; but there was also a large patch of floating reef running north and south in No. 8 road.