been through the long ages of geological history. Decay and renovation in never-ending cycles have followed each other since the beginning of time.

But amid these cycles there has been a marvellous upward progress of organic being. It is undoubtedly the greatest triumph of geological science to have demonstrated that the present plants and animals of the globe were not the first inhabitants of the earth, but that they have appeared only as the descendants of a vast ancestry, the latest comers in a majestic procession which has been marching through an unknown series of ages. At the head of this procession we ourselves stand, heirs of all the progress of the past and moving forward into the future wherein progress towards something higher and nobler must still be for us, as it has been for all creation, the guiding law.

APPENDIX.

THE VEGETABLE KINGDOM.

I. CRYPTOGAMS OR FLOWERLESS PLANTS.1

THESE bear spores that differ from true seeds in consisting only of one or more cells without an embryo. They include the following

classes :

Algæ-Fungi. -These embrace the smallest and simplest forms of
vegetation-fresh-water confervæ, desmidiæ, mushrooms, lichens,
sea-weeds, etc. Some of them secrete carbonate of lime and
form a stony crust, as in the case of the marine nullipores.
(p. 112), others secrete silica, as in the frustules of diatoms
(p. 111). These hard parts are most likely to occur as fossils;
but impressions of some of the larger kinds of sea-weeds may be
left in soft mud or sand (p. 319). Fungi are not well adapted
for preservation, but traces of them have been noticed even in
rocks of the Carboniferous period.

Characeæ are fresh-water plants, some of which abstract carbonate
of lime from the water and deposit it as an incrustation on their
surface. Hence their calcified nucules or spiral seed-like bodies
[gyrogonites] and stems may accumulate at the bottom of
lakes.

Muscineæ, mosses, and liverworts afford little facility for fossilisation. But some of the mosses (sphagnum, etc.) form beds of peat (p. 109).

Filices, ferns, bearing fronds on which are placed the sporangia or spore-cases. Many of them possess a tough tissue which can for some time resist decomposition. Traces of ferns are consequently abundant among the fossiliferous rocks.

Ophioglossaceæ, adder's tongues and moonworts.
Rhizocarpeæ, pepperworts.

Equisetaceæ, horse-tails, with hollow striated siliceous jointed
stems or shoots. These stems possess considerable durability,
and where buried in mud or marl may retain their forms for an
indefinite period. Allied plants [Calamites] have been abun-
dantly preserved among some of the older geological formations
(Old Red Sandstone, Carboniferous, Permian).

Lycopodiaceæ, club-mosses, plants with leafy branches like mosses, growing in favourable conditions into tree-like shrubs that might be mistaken for conifers. Their dichotomous stems and their fertile branches, which resemble cones and bear spore-cases, offer themselves for ready preservation as fossils. The spores are highly inflammable, and it is worthy of notice that similar spores have been detected in enormous abundance in the Carboniferous system. Lycopodium and Selaginella are familiar living genera. (For extinct forms see p. 355.)

II. PHANEROGAMS OR FLOWERING PLANTS.

i. Gymnosperms or plants with naked seeds; that is, seeds not enclosed in an ovary.

Cycadeæ, small plants resembling both palms and tree-ferns. The pinnate leaves are hard and leathery, and have been frequently preserved as fossils. Cycas and Zamia are two typical genera (see pp. 382, 390).

Gnetaceæ, joint-firs, small trees or shrubs with jointed stems (Gnetum, Ephedra, Welwitschia).

ii. ANGIOSPERMS, or plants bearing their seed within an ovary. They are subdivided into two great classes-the Monocotyledons or Endogens, and the Dicotyledons or Exogens.

Monocotyledons, so called from their having only one cotyledon or seed-lobe. They are also known as "Endogens," from the fact that they chiefly increase in diameter by growth in the interior, whereby the exterior layers are pushed outwards. Their seeds are usually enclosed in strong sheaths or shells, of which the cocoanut is a striking example. The following are some of the families :

Lemnaceæ (duck-weeds); Potamogetoneæ (pond-weeds) ; Pandanaceæ (screw-pines); Palmaceae (palms); Typhaceæ (typhads, marshy plants); Cyperaceæ (sedges); Gramineæ (grasses); Juncaceæ (rushes); Liliaceæ (lilies); Irideæ (irises); Dioscoreaceæ (yams); Taccaceæ (tacca); Musaceæ (plantains and bananas); Zingiberaceæ (gingerworts); Orchideæ (orchids).

Dicotyledons or plants that have two cotyledons or seed-lobes ; also called "Exogens," because their stems increase by successive layers added to the exterior. This division includes the most highly organised members of the vegetable kingdom. Our common flowers and hardwood trees belong to it. The sections, orders, and families into which it has been partitioned are so numerous that only some of the more interesting or important to the geologist can be inserted here. It is chiefly the leaves and seeds that occur in the fossil condition and furnish means of recognising the plants.

Urticaceæ (nettles); Platanaceæ (planes); Cannabineæ (hemps); Ulmaceæ (elms); Betulaceæ (birches); Nelumbiaceæ (lotus plants); Nymphæaceæ (water-lilies); Ranunculaceæ (crowfoots); Anonaceæ (custard-apples); Berberideæ (barberries); Laurineæ (laurels); Myristicaceæ (nutmegs); Papaveraceæ (poppies); Fumariaceæ (fumitories); Cruciferæ (plants with cross-shaped flowers, such as wallflower, Brassica, which is the original genus from which our cultivated cabbage, cauliflower, broccoli, and turnip are derived, Sinapis or mustard, cress, radish, etc.); Convolvulaceæ (bindweeds); Solanaceæ (nightshades, potato); Bignoniaceæ (trumpet flowers); Plantagineæ (ribworts or plantains); Labiatæ (plants with labiate flowers, such as mint, sage, lavender); Oleaceæ (olives); Jasminiaceæ (jasmines); Gentianaceæ (gentians); Valerianaceæ (valerians); Cucurbitaceæ (cucumbers and gourds); Campanulaceæ (bellflowers); Compositæ (plants with compound flowers) ; Primulaceæ (primroses); Ericaceæ (heaths); Rhamnaceæ (buckthorns); Sapindaceæ (soap-trees); Balsamineæ (balsam-tribe); Geraniaceæ (cranesbills, geraniums); Euphorbiaceæ (spurge tribe); Araliaceæ (ivy tribe); Cornaceæ (dogwood tribe); Saxifragaceæ (saxifrage tribe); Proteaceæ (found principally in Australia and Cape of Good Hope); Papilionaceæ (plants bearing flowers like those of the pea, bean, clover, etc.); Pomeæ (apple tribe); Rosaceæ (rose tribe); Amygdaleæ (almond tribe); Myrtaceæ (myrtle tribe); Cactaceæ (Indian figs, cactus tribe); Myricaceæ (galewort tribe); Juglandeæ (walnut tribe).

THE ANIMAL KINGDOM.

I. INVERTEBRATES.

I. PROTOZOA. --Animals simple in structure and usually minute in size, with bodies composed of a structureless jelly-like substance (sarcode) which, in some cases, secretes siliceous or calcareous needles, or shells which serve to protect them. It is only these hard parts which have any chance of being preserved as fossils.

CLASS i. RHIZOPODS, having generally a calcareous shell or siliceous skeleton; divided into the following three orders :

Foraminifera-having usually a calcareous shell pierced with
fine pores through which slender thread-like processes pro-
trude from the jelly-like body. These minute creatures
live in enormous abundance in various parts of the ocean,
and their shells gather as a deposit of ooze at the bottom
(Globigerina, Lagena, Nummulina). Their remains are
also found in the geological formations, sometimes constitut-
ing masses of limestone (Figs. 146, 195).

Heliozoa-fresh-water forms sometimes with a radial siliceous
skeleton (Acanthocystis, Clathrulina).
Radiolaria--marine creatures with radial siliceous skeleton,
which usually consists of small siliceous needles or spicules
united together. They occur in vast numbers on some parts