On the Earliest known Vestiges of Vertebrate Life; being a Description of the Fish Remains of the Old Red Sandstone Rocks of Forfarshire

The middle Ludlow beds, in the neighbourhood of Leintwarden, have, I believe, yielded the earliest vestiges of vertebrate life, a fragment of Pteraspis, or at least of a closely allied genus, having been discovered there some time ago. In the upper Ludlow rocks and Downton beds ichthyic remains become abundant, but in a sadly imperfect condition. In these localities, associated with Pterygotus, Platyschisma helicites, Lingula cornea, &c., are remains of the Cephalaspidæ; while the Ludlow and Downton bone-beds are full of broken fragments of bones, spines, detached scales, and such like. The cornstones of Hereford have been found to contain similar remains. The Cephalaspid remains are for the most part readily recognised, all the rest are so broken up and fragmentary that, but for the light our Scottish Old Red Sandstone rocks have cast on these olden fishes, their nature and relations would have been comparatively unknown.

None of our Scottish rocks affording fish remains are older than the lowermost beds of the Old Red Sandstone, and hence not so ancient as those of the above mentioned English localities, which, as Platyschisma helicites, Lingula cornea, and Beyrichia are also common to the Lesmahagow Upper Silurian or Passage Beds, appear to belong to a period immediately antecedent to that of the Scottish rocks affording our earliest known fish remains. Cephalaspis has long been known as a characteristic fossil of the Forfarshire Sandstones. Pteraspis was first discovered in Scotland by the Rev. Hugh Mitchell, in a quarry near Bridge of Allan, in