On the fossil remains of reptiles, and on chelonian foot-tracks, from the Devonian strata of Morayshire / by Lambart Brickenden and Gideon Algernon Mantell.

  • Brickenden, Lambart.
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: On the fossil remains of reptiles, and on chelonian foot-tracks, from the Devonian strata of Morayshire / by Lambart Brickenden and Gideon Algernon Mantell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    On supposed Fossil Eggs of Reptiles, from the Devonian Rocks of Forfarshire. In connection with the announcement of the discovery of fossil reptiles in the Old Red of Morayshire, I would offer a few remarks on certain organic remains that occur in the more ancient Devonian strata of Forfarshire, and which are popularly termed “petrified black- berries,” and have been considered by some naturalists to be seeds, by others the ova of gasteropodous Mollusca. These fossils are small, carbonaceous, oval bodies, more or less de- pressed, and are figured by Sir Charles Lyell with the following ob- servations* :— “ In the same grey paving-stones and coarse roofing-slates in which the Cephalaspis occurs, in Forfarshire and in Kincardineshire, the remains of marine plants or fucoids abound. They are fre- quently accompanied by groups of hexagonal, or nearly hexagonal, markings, which consist of small carbonaceous bodies placed in a slight depression of the sandstone or shale. These much resemble in form the spawn of the recent Natica, in which the eggs are arranged in a thin layer of sand, and seem to have acquired a polygonal form by pressing against each other. The substance of the egg, if fossilized, might give rise to small pellicles of carbonaceous matter. These fossils I have met with both at the foot of the Grampians, north of the valley of Strathmore, and in the vertical shale beneath the conglome- rate, and in corresponding beds in the Sidlaw Hills ; always occupy- ing the same situation, and without any intermixture of shells, whe- ther marine or freshwater.” Several years ago my attention was directed to this subject from having obtained, from some indurated mud thrown up from the bottom of a long dried-up pond on Clapham Common, a carbonized mass of the ova of a Frog (Rana temporaria), which so closely re- sembled the petrified eggs of Forfarshire, that I suggested to Sir Charles Lyell the much greater probability that the latter were re- ferable to batrachians than to gasteropodous mollusks ; but, although the analogy was admitted, the fact that no traces of reptiles had at that time been discovered in any formation more ancient than the Trias, was regarded as fatal to such au interpretation. On receiving the fossil reptile from Elgin, the idea of the batra- chian origin of the “ petrified blackberries ” again recurred to my mind, and from a careful examination of all the specimens within my reach, and a comparison of the fossil ova with those of the Frog in a carbonized state, I have no hesitation in expressing my conviction, that if the animal origin of the carbonaceous bodies found in the shales of Forfarshire be proved, there is no doubt that they are the ova of batrachians closely allied to the Ranidce or Frog tribe. The fossil eggs occur in clusters blended with the foliage of ap- parently fluviatile plants. Their forms are in many instances well defined, and the polygonal depressions, apparently produced by the * Manual of Elementary Geology, 3rd edition, p. 344.