494 Professor T. G. Bonney— Basalt of the Moahite Stone. 



repaired stone is now in the Louvre Museum,^ The late Professor 

 E. H. Palmer, on a visit to Dhiban in 1870, picked up a small 

 fragment from those still lying on the spot, which he gave to me on 

 his return to England. The constant pressure of other work has 

 hitherto prevented me from examining the specimen, and I have 

 only recently had a slice prepared. The largest face of the fragment 

 measures about Z" x 2-5", but the thickest part hardly exceeds half 

 an inch. The original smoothed surface of the stone, possibly 

 including part of a letter, may be seen on one of the sloping sides. 



The rock apparently is in good preservation ; minutely granular, 

 nearly black in colour, but proving on a closer examination to be 

 speckled with more than one dark mineral, and with less definite 

 greyish spots, all very small. Its specific gravity (by a Walker's 

 balance) is 2-89. The slice, when examined under the microscope, 

 exhibits a porphyritic structure, though on a small scale, no one of 

 the minerals exceeding about "05" in diameter. They are : — (a) 

 Augite, not abundant, brown in colour, the grains presenting a rather 

 corroded aspect both externally and even internally, partially 

 including, in one instance, a small grain of the next mineral. 

 (6) Olivine, rather abundant, rounded or slightly irregular in outline, 

 occasionally showing a fairly well-developed brachypinacoidal and 

 an imperfect macropinacoidal cleavage. A brown staining has 

 affected the exterior of most grains, and penetrated for a short 

 distance into cracks. This, in addition to a very faint yellowish 

 tinge in the grains, shows the olivine to be a rather ferriferous 

 variety, (c) Iron-oxide, hematite, or perhaps ilmenite, with a rusty- 

 looking exterior ; {d) felspar : this, like the last-named mineral, 

 varies so much in size that it is difiicult to draw the line between 

 crystals occurring porphyritically and those in the base. In no 

 case do the extinction angles give very decisive evidence, but they 

 suggest that labradorite is at any rate the dominant species. 



The minutely holocrystalline groundmass, except for one or two 

 small patches, consists of lath-like plagioclases, up to about -004" in 

 length ; of stumpy, not very well-formed prisms of brown augite, 

 .about -002", and of granules of iron-oxide. The patches, small ^ and 

 not numerous, are formed by a fairly clear mineral, which, however, 

 includes some very minute films, giving bright polarization tints, its 

 own being very low, not rising above a greyish or slightly pinkish 

 white. Each patch generally consists of two or three grains, and is 

 without a definite external form. The small felspars and augites 

 are sometimes included by or project into these patches from the 

 surrounding matrix, which has no regular boundary. The mineral 

 resembles a lime carbonate (there is no distinct cleavage), and 

 I observed, on applying some hydrochloric acid to the cut surface, 

 a rather brisk effervescence at a number of points ; hence, I conclude 

 it must be calcite, probably not very pure. But though it occurs 



^ Palmer: "Desert of the Exodus," pt. 2, ch. x. For the inscription see 

 Ginsburg, " Moahite Stone." A figure and succinct account are given in Chambers' 

 Encyclopfedia, s.v. Moabite Stone. 



* The diameter of the largest is about 'OS". 



