It contains, besides, in considerable abundance, though in a state of very imperfect preservation, scales that differ from those of the _Holoptychius_, and from one another. One of these, figured and described by Professor Fleming in _Cheek's Edinburgh Journal_, bearing on its upper surface a mark like a St. Andrew's cross, surrounded by tubercled dottings, and closely resembling in external appearance some of the scales of the common sturgeon, "may be referred with some probability," says the Professor, "to an extinct species of the genus _Accipenser_."[AS] [Footnote AS: May I crave the attention of the reader to a brief statement of fact? I have said that Professor Fleming, when he minutely described the scales of the _Holoptychius_, hazarded no conjecture regarding the generic character of the creature to which they had belonged; he merely introduced them to the notice of the public as the scales of some "vertebrated animal, probably those of a fish." I now state that he described the scales of a contemporary ichthyolite as bearing, in external appearance, a "close resemblance to some of the scales of the common sturgeon." It has been asserted, that it was the scales of the _Holoptychius_ which he thus described, "referring them to an extinct species of the genus _Accipenser_;" and the assertion has been extensively credited, and by some of our highest geological authorities. Agassiz himself, evidently in the belief that the professor had fallen into a palpable error, deems it necessary to prove that the _Holoptychius_ could have borne "no relation to the _Accipenser_ or sturgeon." Mr. Murchison, in his _Silurian System_, refers also to the supposed mistake. The person with whom the misunderstanding seems to have originated is the Rev. Dr. Anderson, of Newburgh. About a twelvemonth after the discovery of Professor Fleming in the sandstones of Drumdryan, a similar discovery was made in the sandstones of Clashbennie by a geologist of Perth, who, on submitting his new found scales to Dr. Anderson, concluded, with the Doctor, that they could be no other than oyster shells; though eventually, on becoming acquainted with the decision of Professor Fleming regarding them, both gentlemen were content to alter their opinion, and to regard them as scales. The Professor, in his paper on the Old Red Sandstone in _Cheek's Journal_, referred incidentally to the _oyster shells_ of Clashbennie--a somewhat delicate subject of allusion; and in Dr. Anderson's paper on the same formation, which appeared about seven years after, in the New Journal of Professor Jameson, the geological world was told, for the first time, that Professor Fleming had described a scale of Clashbennie _similar to those of Drumdryan_, (_i. e._, those of the _Holoptychius_,) as bearing a "close resemblance to some of the scales on the common sturgeon," and as probably referable to some "extinct species of the genus _Accipenser_." Now, Professor