The Burdiehouse limestone is an evident fresh water formation, situated below the Edinburgh coal-field, and belongs to the carboniferous limestone strata contiguous, forming a partial and local deposit. Besides the ichthyological remains discovered and described by Dr Hibbert, (Edinburgh Philosophical Transactions, vol. xiii.) and enumerated in my Geological Sketch of the Environs of Edinburgh, I have since found several fragments of bones, which appear to me to belong to animals of a higher class than fishes, and probably to the class reptilia. One bone, five inches in length and four in breadth, has much the appearance of a coracoid bone of some unknown reptile.

The bones figured in the annexed plate are of the natural size, from a slab of the same limestone; the bone a is exactly the shape of the larger specimen in my possession. There are two similar ones in the same piece of limestone, and two the same as b. Both these latter are imperfect, but the fragments have a resemblance to scapular bones.

These bones differ from those of fishes in having a more compact structure, and a less fibrous appearance, in having well defined edges and furrows, marking out the situation of blood-vessels traversing their surface. The bodies c care of frequent occurrence in this locality. They differ from the scales of the ganoid order of fishes, also abundantly found, resemble somewhat the scales of the cycloid order, but may be the dermal scales of some reptile.

I have also found two portions of jaw bones, with numerous small teeth, which are figured e, e, somewhat magnified; ƒ are the same still more magnified, and evidently resemble the teeth of a shark. These teeth are very numerous in the jaws, indicating the double and