to cut me down, or to knock me on the head. I am afraid this chapter would require a long apology, and for a long apology space is wanting. But there will be no egotism, and much geology, in my next. CHAPTER XI. Ichthyolite Beds--An interesting Discovery--Two Storeys of Organic Remains in the Old Red Sandstone--Ancient Ocean of Lower Old Red--Two great Catastrophes--Ancient Fish Scales--Their skilful Mechanism displayed by examples--Bone Lips--Arts of the Slater and Tiler as old as Old Red Sandstone--Jet Trinkets--Flint Arrow-heads--Vitrified Forts of Scotland--Style of grouping Lower Old Red Fossils--Illustration from Cromarty Fishing Phenomena--Singular Remains of Holoptychius--Ramble with Mr. Robert Dick--Color of the Planet Mars--Tombs never dreamed of by Hervey--Skeleton of the Bruce--Gigantic Holoptychius--"Coal money Currency"--Upper Boundary of Lower Old Red--Every one may add to the Store of Geological Facts--Discoveries of Messrs. Dick and Peach. I spent one long day in exploring the ichthyolite beds on both sides the Cromarty Frith, and another long day in renewing my acquaintance with the Liasic deposit at Shandwick. In beating over the Lias, though I picked up a few good specimens, I acquired no new facts; but in re-examining the Old Red Sandstone and its organisms I was rather more successful. I succeeded in eliciting some curious points not yet recorded, which, with the details of an interesting discovery made in the far north in this formation, I may be perhaps able to weave into a chapter somewhat more geological than my last.