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tlie Secondary formations, in their character as original de-posits, 'whose strata still occur in the order in which theywere first laid down. We find, however, in Banff and Aber-deenshires, and more partially in Caithness, remains of theCretaceous system, occurring in some localities in the charac-ter of re-formations. A deposit at Moreseat, near Cruden,elaborately described by Mr William Ferguson, late of Glas­ gow , seems to be almost exclusively a re-formation of theGreensand; and on the Hill of Dudwick, near Ellon, thereare vast accumulations of flints, in which the Bev. Mr Long-muir of Aberdeen, who has carefully explored the locality,detected many of the characteristic Cretaceous fossils furnish-ed by the chalk of England. I have examined beds of gravela few miles to the south of Peterhead, in which there occursmerely a per centage, though a not inconsiderable one, of thesechalk flints ; but I have been informed by our ingenious cor-responding member, Mr Peach, with ■whom I saw several ofthe Cretaceous organisms of the locality, that, had I set my-self to examine in a different direction, more to the north andwest, I would have found thick gravel beds composed of chalkflints almost exclusively. The best collections yet made ofthe organisms of this denuded system, of which only thebroken fragments survive, are those of Mr Longmuir, repre-sentative of the Scottish Chalk, and of Mr Ferguson, repre-sentative of the Scottish Greensand. Both are inadequatelyrepresented in my collection ; and what it possesses I owechiefly to the kindness of Mr Longmuir, and to that of MrDick, the original discoverer of the Chalk in Caithness, whereit occurs, however, merely in detached fragments in theboulderclay. Much need not be expected from the organic remainsof a deposit so broken and scattered. I have seen in its flints,however, finer and more delicately preserved specimens of &Flustra, that not a little resembles our existing Flustra fo.liacea, than any I have yet succeeded in detecting in those