The absence of all shells, so far as our researches have yet gone, in the slates and sandstones of Scotland above alluded to, raises a presumption against their marine origin, and a still stronger one against the fossil eggs being those of Gasteropoda. It is well known that a single female of the Batrachian tribe ejects annually an astonishing quantity of spawn. Mr. Newport, author of many accurate researches into the metamorphoses of the Amphibia, having examined my fossils from Forfarshire, concurs in Dr. Mantell's opinion that the clusters of eggs (figs. 397. 398. p. 344.) may be those of frogs; while other larger ones, occurring singly or in pairs in the same slates, and often attached to a leaf, may be the ova of a gigantic Triton or Salamander. (See figs. 523, 524, 525.) I may observe that the subdivision of the Old Red Sandstone, in which these plants and ova occur (No. 4. of the section, fig. 62. p. 48.), is considerably lower in position than the rock in which the Telerpeton of Elgin is imbedded. [Illustration: Fig. 523. Fossil.--Old Red. Fig. 523. Slab of Old Red Sandstone, Forfarshire, with eggs of Batrachians. _a._ Ova in a carbonized state. _b._ Egg cells; the ova shed.] [Illustration: Fig. 524. Recent. Fig. 524. Eggs of the common frog, _Rana temporaria_, in a carbonized state, from a dried-up pond in Clapham Common. _a._ The ova. _b._ A transverse section of the mass exhibiting the form of the egg-cells.] [Illustration: Fig. 525. Eggs of Batrachians.--Old Red Sandstone. Fig. 525. Shale of Old Red Sandstone, or Devonian, Forfarshire, with impression of plants and eggs of Batrachians. _a._ Two pair of ova resembling those large Salamanders or Tritons on the same leaf. _b b._ Detached ova. _c._ Egg-cells of frogs or _Ranina_.]