dilia, though distinct from any known form of that age, was for the first time asserted, and, indeed, I may say, demonstrated, the remains placed in my hands enabling me to put the fact beyond doubt. At the same time I mentioned the existence in the same beds of " a Saurian reptile about 6 feet long, remarkable for the flattened or slightly concave articular surfaces of the centra of its vertebrae, and for its well-developed costal system and fore and hind limbs, but more particularly characterized by its numerous series of subcylindrical palatal teeth," I named this new reptile Hyperodapedon Gordoni, in honour of its discoverer, the Rev. Dr. Gordon, to whose exertions in the Elgin country geology owes so much : and I stated that " its marked affinity with certain Triassic reptiles, when taken together with the resemblance of Stagonolepis to Mesozoic Crocodilia, lead one to require the strongest stratigraphical proof before admitting the Palaeozoic age of the beds in which it occurs."
Sir R. I. Murchison admitted that his belief in the Devonian age of the Elgin sandstones was " somewhat shaken " by the discovery of the nature and affinities of these reptilian remains.
In the ten years which have elapsed since the papers to which I have referred were read before the Society, the age of the reptiliferous sandstones of Elgin has been repeatedly discussed by some of the most eminent of English geologists, with the general result that while one half of the disputants produced excellent reasons for believing them to be of Mesozoic date, the other half adduced no less weighty arguments in favour of their Palaeozoic age. And it is a curious circumstance that in this Geological Siege of Troy, Priam has been fighting the battle of the Greeks, and Nestor that of the Trojans, — Sir R. Murchison, whose general geological views would naturally incline him to assign a later date to these Elgin reptiles, having been the sturdiest champion of their Devonian age; while Sir Charles Lyell, who ought to rejoice if they could be made out Palaeozoic, has as strongly fought for their belonging to the Trias. Without meaning to compare myself to Achilles, I may say that "under these circumstances " I thought it best to retire to my tents and take no part in the fray until my palaeontological armoury should yield more efficient weapons. And as my excellent friend Dr. Gordon supplied me from time to time with new specimens, I lived in hope that one day or other I should be able to make an effective sally.
No such opportunity presented itself, however, until the year 1867, when a number of important facts came to light in singular coincidence, and, as I conceive, rendered the proper discussion of the question and the drawing of satisfactory conclusions somewhat easier than before.
I may premise that the original specimen of Hyperodapedon is in a very bad condition, the substance of the bones and teeth being extremely friable and decayed. It is nevertheless sufficiently clear that the roof of the mouth is provided with several parallel rows of teeth, that the edge of the ramus of the lower jaw is also beset with a series of close-set or even confluent teeth, and that the mandibular
