[Footnote AI: I find, by some notes, which had escaped my notice when drawing up for the _Witness_ newspaper the sketches now expanded into a volume, that in the year 1834 I furnished the collection of a geological friend, the Rev. John Swanson, minister of the parish of Small Isles, in the Outer Hebrides, with a well-marked specimen of the _Pterichthys Milleri_. The circumstance pleasingly reminds me of the first of all my early acquaintance, who learned to deem the time not idly squandered that was spent in exploring the wonders of bygone creations. Does the minister of Small Isles still remember the boy who led him in quest of petrifactions--himself a little boy at the time--to a deep, solitary cave on the Moray Frith, where they lingered amidst stalactites and mosses till the wild sea had surrounded them unmarked, barring all chance of retreat, and the dark night came on?] CHAPTER VII. Further Discoveries of the Ichthyolite Beds.--Found in one Locality under a Bed of Peat.--Discovered in another beneath an ancient Burying-ground.--In a third underlying the Lias Formation.--In a fourth overtopped by a still older Sandstone Deposit.--Difficulties in ascertaining the true Place of a newly-discovered Formation.--Caution against drawing too hasty Inferences from the mere circumstance of Neighborhood.--The Writer receives his first Assistance from without.--_Geological Appendix_ of the Messrs. Anderson, of Inverness.--Further Assistance from the Researches of Agassiz.--Suggestions.--Dr. John Malcolmson.--His Extensive Discoveries in Moray.--He submits to Agassiz a Drawing of the _Pterichthys_.--Place of the Ichthyolites in the Scale at length determined.--Two distinct Platforms of Being in the Formation to which they belong.