John MacCulloch

“ The continuity of the lines of colour precludes all possibility of a succession of deposited layers, otherwise than in those very lines, and affords at the same time a proof, if any were wanting, that the fissile property of this killas has not been the result of stratification. The whole must in fact be considered as formed either of one deposit, of a semifluid red mud, coloured afterwards by a mixture of blue mud, or of successive layers of red and blue mud. ”

“ It is well known that the operation of marbling, either in oil or water, is produced by partially mixing together two or more coloured fluids of considerable density or tenacity: should the layers of the several fluids have been straight, the curved and wavy appearance is given by producing short and partial disturbances in different parts of the compound. ”

“ The general colour of the mass is a faint brown red, and a number of dove-coloured stripes of unequal thickness may be seen traversing it in very irregular curved lines, but bearing a sort of parallelism or relation to each other. ”