I might multiply remarks and instances such as these; but it is not needed. Every one will form their own opinion, in collecting fossil pebbles, as to what the _originals_ were; but I think they will generally agree with me, that while our living individuals differ in many points, still we have mostly types of the same species actually existing in our present seas. What all connoisseurs, and even amateurs, should do, is to preserve every remarkable specimen they may obtain, along with an accurate note of where they got it. It is a great pity that, among so many persons who have at once discernment and a liking for this branch of Mineralogy, there are so few who will be at the trouble of what lawyers call “taking minutes” of the evidence which comes before them in the course of the pursuit. I have looked over several fair enough collections made by amateurs; but, with one exception, I never knew an instance in which the collector could tell me, with any degree of certainty, from what particular beach he had gathered this or that specimen. Of course, when a scientific investigation is proposed, such omission renders the most valuable part of the collection comparatively useless. For the locality is all-important. A pebble may thus be always traced to its geological “home” or birthplace. It can only have had one of three sources: either it was first dropped _here_, where you find it; or, it is a “travelled” pebble, having come round from some distant beach; or, it is an offering from the deep sea. The latter case is of exceedingly rare occurrence, and need hardly be taken into account; nevertheless, for truth’s sake, and to include all possible varieties, I cite it here. A genuine deep-sea pebble is a waif which I have only twice, as yet, met with in my sea-side experience. One of these was, I think, fished up in a dredging-net; the other was thrown on the beach during a storm. In both instances, the fossil was a “choanite,” and bore the marks of having been washed out of a limestone rock. The age of such fossil could not have been less than 4000 years, the date of Noah’s deluge, for obvious reasons; but it may have been considerably greater. If there were any known method of softening these pebbles to a consistency like that of melted glue, we might learn something concerning their past history; but I am not aware of the existence of any such process at present. _Silex_, once hardened into the condition in which we meet with it, is a most intractable substance to deal with; and the very fact of its having at one time been viscous, renders it highly improbable that, in the course of nature, its texture will ever assume a plastic character again. Moreover, while the majority of our flints are concretions, there are some which are semi-crystalline. These latter, it is evident, cannot now advance to the stage of perfect crystals; but neither can they retrograde: the next change which awaits so hard a substance must be, to crumble away.