discovered two species of Coleoptera (Curculionide), and a Neuropterous Insect (Corydalis)1. But the most remarkable illustration of the utility of this kind of hopeful search is afforded by the discovery of a landshell, allied to if not identical with Pupa, in the interior of a fossil tree (Sigillaria), in the Coal-formation of Nova Scotia, by Sir C. Lyell and Dr Dawson. Remains of Land Reptiles (Dendrerpeton and Hylonomus), and a Chilognathous Myriapod (Xylobius). An airbreathing Gasteropod of a modern genus, airbreathing Reptiles, Insects of two recognized orders, and a Myriapod, these suggest and indeed imply the existence of many more forms of terrestrial animals so as to constitute a Fauna of the Carboniferous age. Precarboniferous we might perhaps say, for plants of the family (Lepidodendra) with which these insects and reptiles and shells are associated occur in earlier strata, being first noticed in the uppermost bands of the Silurian system.

Terrestrial plants are scattered at intervals through most of the Marine Strata, above the Silurian Rocks, thus indicating the force and frequency of affluents from the land. They were collected in considerable quantity in estuarine and lacustrine deposits of the Carboniferous and Oolitic eras, and in lagoons of salt water, as at Stonesfield, having been, perhaps, blown into these latter situations with Neuropterous and Coleopterous Insects, among the latter, Buprestidæ and Curculionidae. In the Palæozoic ages are no Cycadacere; in the Neozoic no Lepidodendra; Ferns abound in several of the deposits in and above the Upper Devonian Strata.

In the lowest beds of the Lias and passage-beds from the Trias, Insects have been collected at the Cliffs of Aust, Westbury and Wainlode, and at several other places in the Vale of the Severn, probably blown into shallow salt water, a common circumstance on the coasts. Others occur more abundantly in the Vale of Wardour and Purbeck1. The census of the fossil orders of Insects runs thus:

Cænozoic... Coleoptera (Copris, Donacia, Harpalus,) in Pleistocene beds, at Mundsley, Norfolk.

(In France most of the Orders of Insects are found in freshwater beds at Aix in Provence).

Mesozoic... Purbeck beds, Coleoptera, Neuroptera, Orthoptera, Homoptera, Diptera.

Oolite of Stonesfield, Coleoptera, Neuroptera.
Lias of Severn Vale, Coleoptera, Neuroptera,
Orthoptera, Homoptera, Diptera.

Palæozoic... Coal-formation, Coleoptera, Neuroptera.

Terrestrial Saurian Reptiles acquired extraordinary magnitude in the Oolitic period, and exhibit as high a grade of organization in Megalosaurus and Iguanodon as the aquatic Crocodilians, of the same ages, Teleosaurus, Steneosaurus, Cetiosaurus and their allies. The earliest traces of Land Saurians are those already alluded to as found in the Nova Scotia coalfield, one of which is supposed to be of Lacertian, the other of Ganocephalic affinity. Perhaps in regard to most of the Saurian fossils we may prudently wait for further information before confidently assigning them to marine, fluviatile, or terrestrial life. Ichthyosaurus is no doubt truly marine, Megalosaurus truly terrestrial; regarding many others we may reserve an opinion.

Of fossil birds our evidence is mostly in footsteps, sometimes, as in Connecticut1 and near Hastings", of such extraordinary magnitude as to match the stride of the Moa of New Zealand. In general the footprints are of the Cursorial order of Birds; marks of their movements are found in the sandy shores of the Permian, Triassic, and Oolitic Seas.

Mammalia of the Marsupial order appear to have the priority in time. The most ancient fossils of this kind yet traced are the small insectivorous teeth found in the Trias of Würtemburg. Next

1 Hitchcock, Mem. American Academy, Vol. πι.

* Beckles, Journal of Geol. Soc.

come the Insectivora of Stonesfield, which in part belong to the Marsupialia1, and one, the latest of the discoveries there, the Stereognathus Ooliticus, which belongs to an artiodactylous order2. Next come the Insectivora and Rodentia of Purbeck, also in part Marsupial. Then as far as yet discovered a blank follows; there is no Mammal known of the Cretaceous period, but the Tertiary Strata reveal several successive groups. The whole series stands thus, if we include more than the British Fauna:

Pleistocene and Pleiocene. Full series of orders of mammalia. Meiocene... Pachydermata and other families.

Eocene......Pachydermatous prevail.

Purbeck

Marsupial Insectivora, Rodentia. Stonesfield..Marsupial Insectivora, Artiodactylous genus. Trias.........Marsupial Insectivora.

ANTIQUITY OF THE EARTH.

Geologists have been much censured for vainly endeavouring to assign measures of time to the seemingly vague and shadowy ages of the Trilobites and Belemnites; nor have they escaped censure for countenancing speculations which assign to the human race a period very much longer than that hitherto adopted on historical grounds. They deserve no rebuke, however, for the endeavour to force their way into the citadel of natural truth, if they undertake the siege after a sufficient survey of the difficulties of the enterprise, which in this case are not slight. Let any one acquainted with the modern aspect of Astronomy, consider well the nature of that problem which, omitting all previous cosmical changes, would count the years since the planet became a terraqueous globe-let him then look at the Mosaic narrative, and be satisfied with the truth, that 'In the beginning God created the heavens and the Earth,' for no measures of time conceivable by man will reach back to that remote epoch in the history of our solar system. That, however, is the starting-point of physical geography, for then began the movements and changes in land, water, and air, which it is the business of geology to register and interpret. As already explained, the gift of life on this earth is limited by conditions within which alone it is possible: until these conditions were attained-that is to say, arrived at in the pre-ordained course of nature-the earth might be well described by the words 'without form, and void.' For the rocky monuments of this period, which we have endeavoured