I may add that I believe all the trees, about thirty in number, which have become exposed in this bed since its discovery, have been ransacked for such remains; and that while the majority have afforded some reward for the labour, some have been far more rich than others in their contents. It is also to be observed that owing to the mode of accumulation of the mass filling the trees, the bones are usually found scattered in every position, and those of different species intermingled; and that being often much more friable than the matrix, much labour is required for their development; while after all has been done, the result is a congeries of fragments. A few specimens only have been found, showing skeletons complete, or nearly so, and I shall endeavour to figure one or two of these by way of illustration in the present chapter. The beds on a level with the top of the reptiliferous erect trees are arenaceous sandstones, with numerous erect _Calamites_. I have searched the surfaces of these beds in vain for bones or footprints of the reptiles which must have traversed them, and which, but for hollow erect trees," would apparently have left no trace of their existence. On a surface of similar character, sixty feet higher, and separated by three coals, with their accompaniments, and a very thick compact sandstone, I observed a series of footprints, which may be those of _Dendrerpeton_ or _Hylonomus_. [Illustration: A typical Carboniferous Microsaurian, _Hylonomus Lyelli_ Restoration showing dermal armour and ornaments. Skeleton restored from measurements of the bones of the type specimen figured at the beginning of the chapter.] Species of Microsauria. Hylonomus Lyelli. In the original reptiliferous tree discovered by Sir C. Lyell and the writer, at the Joggins, in 1851, there were, beside the bones of _Dendrerpeton Acadianum_, some small elongated vertebræ, evidently of a different species. These were first detected by Prof. Wyman, in his examination of these specimens, and were figured, but not named, in the original notice of the specimens. In a subsequent visit to the Joggins I obtained from another erect stump many additional remains of these smaller reptiles, and, on careful comparison of the specimens, was induced to refer them to three species, all apparently generically allied. I proposed for them the generic name _Hylonomus_, "forest dweller." They were described in the Proceedings of the Geological Society for 1859, with illustrations of the teeth and other characteristic parts.[136] The smaller species first described I named _H. Wymani_; the next in size, that to which this article refers, and which was represented by a larger number of specimens, I adopted as a type of the genus, and dedicated to Sir Charles Lyell. The third and largest, represented only by a few fragments of a single skeleton, was named _H. aciedentatus_. This I had subsequently to remove to a new genus, _Smilerpeton_.