Page:Quarterly Journal of the Geological Society of London, vol. 29.djvu/187

 clusively establish, as I believe, the Secondary- age of the long-disputed beds (fig. 14).

The beds referred to are seen at Dunrobin to underlie conformably a considerable thickness of strata, which I shall demonstrate by most abundant palaeontological evidence to be of the age of the Middle and Lower Lias. With these Mesozoic strata the formation in question agrees both in strike and dip, while with the Old Red Sandstone strata, which are exhibited in close proximity, it has no common relations whatever. Indeed, the strata in question appear to have been seen by Sir R. I. Murchison, though probably not under favourable conditions, and were by him unhesitatingly placed in the Secondary series.

There are two objections which may possibly be urged against the view which I have taken of the relations of this formation in Sutherland.

It may be said that the agreement in strike and dip of the strata at Dunrobin may be accidental, and that the Lias strata, instead of overlying the calcareous and cherty rock, may be faulted against it. This objection may appear to receive some support from the facts which I have already pointed out, indicating the greatly faulted condition of these Sutherland rocks.

To this objection there is fortunately the most complete answer. The lowest beds of the Lias series, as is so often the case, consist of a conglomerate ; and among the pebbles in these beds are numerous fragments of the peculiar calcareous and cherty rock so frequently referred to.

It may also be urged that possibly the conformity of the beds of the formation in question with the overlying Lias strata may be accidental, and that in spite of it they may be of as early date as the Old Red Sandstone.

In reply to this objection I would point to the fact that in Golspie Burn the Cherty Rock of Stotfield is seen at only a very short distance from beds of undoubted Old Red Sandstone strata, and that while the latter are greatly disturbed and dip S.E., at an angle of 70°, the former dips N.N.E. 12°, conformably to the great mass of Secondary strata here. The facts now adduced with regard to the stratigraphical relations of the " Cherty Rock of Stotfield" and the underlying sandstone (which we cannot hesitate to recognize as the

Fig. 14.-Section exposed in the reefs below Dunrobin Castle.

r, r. Shingle.

a. " Reptiliferous Sandstones." Trias.

b. " Cherty Rock of Stotsfield."

c. Sandstones and conglomerates with pebbles derived from a and b (Rhaetic?)

d. Estuarine series-sandstones, shales, and coals, plant-remains, &c. ILias a?).

e. Alternations of clays and shelly limestones; marine fossils (Lias B).

f. Blue micaceous clays; marine fossils (Lias y).