Vol. 62.] STRUCT1J.RE OF THE SGTJKR OF EIGG. 59 



the relative proportions of these two varying, though the former 

 element is always well represented. There are angular blocks of 

 Torridonian sandstone up to 4 feet in diameter, besides smaller 

 fragments. Some of the pieces of basalt measure from 1 to 2 feet 

 in diameter, and they are mostly subangular in shape. Of more 

 local distribution in a recognizable state is the soft Oolitic sand- 

 stone. Pieces of this are abundant in places, generally in a 

 crumbling condition, and the sandy element in the matrix of the 

 deposit may be attributed to this source. Mingled with the pieces 

 of Oolitic sandstone are fragments of brown wood, different from 

 the black wood already mentioned. Other materials than those 

 now enumerated seem to be very rare. I possess a piece of flint 

 found here many years ago by Mr. C. S. Middlemiss. 



At the spot where the section (fig. 5, p. 57) is drawn it is not 

 possible to say whether any other deposit intervenes between the 

 breccia with Torridonian and other extraneous debris (Z) and the 

 underlying basalts. Some 10 yards to the east, however, a bedded 

 sandstone is seen lying below the breccia, or constituting the lower 

 part of it (S in fig. 6, p. 60). It encloses blocks and smaller fragments 

 of Torridon Sandstone and basalt like those in the breccia proper, 

 but here the matrix makes up the greater part of the mass. It is 

 a tine-textured grey sandstone, composed of quartz-grains, with a 

 cement mainly calcareous, though basaltic material, perhaps of the 

 nature of volcanic ash, also enters into its composition. The thick- 

 ness seen is about 2 feet. In addition to rock-fragments, the 

 sandstone encloses abundant fossil wood, and there is a band com- 

 posed almost wholly of vegetable remains in the condition of lignite. 

 The stratification, which was indistinguishable in the coarse breccia, 

 is here very evident; and there is a general resemblance to the thin 

 and inconstant stratified deposits with plant-remains intercalated 

 at various horizons in the basalt-group in Skye and other parts of 

 the region. 1 



Sir Archibald Geikie considered the breccia to be a fluviatile deposit 

 of the pitchstone-epoch, the sandstone-fragments being brought 

 down by a river from more or less distant sources, and the pine- 

 wood representing a contemporaneous vegetation. This interpret- 

 ation seems, however, to involve considerable difficulties. The 

 high proportion of extraneous fragments as compared with the local 

 basalt, the large size and angular form of some of the blocks, and 

 the mingling of coarse and fine material, are all difficult to explain 

 on this hypothesis. Nor is it easy to find a source for the Torri- 

 donian and Jurassic rock-fragments. It must be remembered that 

 the epoch of the pitchstone was long subsequent to any differ- 

 ential movements of elevation and subsidence known in the region ; 

 and therefore the relative altitudes of the several formations were 

 substantially as they are to-day. We can scarcely suppose that the 

 pre-Tertiary strata were more freely exposed at the surface then 



1 See, for instance, Sir Archibald Geikie, Quart. Journ. Geol. Soc. vol. lii 

 (1896) pp. 341-42. 



