NATURAL HISTOKY OF THE PKIMEVAL WORLD. 



27 



Inrgci- branches ; others, again, were of zig-zag shape, 

 01- inilentcd like tlie steps of a staircase, sweeping from 

 the ground to a giddy height." 



Some such scene, allowing for differences of form 

 aiid colour, and a more monotonous vegetation, we 

 may fancy to have been presented by a Middle Oolitic 

 landscape. 



Let us suppose that we have made our way through 

 this dense growth of cycads and conifers, palms and 

 ferns, and are standing on the brink of a limestone cliff, 

 looking out afar upon a wide expanse of sea. The 

 animal life that meets our gaze, and which our artist 

 has endeavoured to reproduce in the engraving (l^late 

 4), greatly differs from any of the forms to which 

 we are now accustomed. The strange, cuirassed, 

 crocodile-like creature that has just emerged from the 

 waves and advances towards us, carrying in its mouth 

 a freshly captured victim, is the Tclcosaiirus, and its 

 prey a Geot/ieulis, a kind of calamary. The teleo- 

 saurus, as already stated, carried a coat of mail both 

 on back and belly, and of this we are made certain by 

 the dead monster floating on its back in the shallow 

 water, and so exposing its ventral cuirass. 



At the foot of the cliff, where it slopes towards the 

 beach, stands a Hi/laosminis — a great land-saurian — 

 with bristling back, whose numbers, as yet, are very 

 limited. 



The tide is up, but if we waited until it receded we 

 bliould find the shore covered with animal life — nautilus 

 and ammonite, turbo, nerina'a, and pleurotomaria; 

 pecten, ostrea, and avicula; encriuites, and legions of 

 polyzoans. 



Our artist has presented us in the accompanying 

 illustration with an ideal landscape peculiar to the 

 period we are now describing (Plate 5). 



Rightly to understand its principal features, we must 

 digress from the immediate subject of this chapter, and 

 glance, as we have previously done, at the prevailing 

 forms of vegetable life. 



The terrestrial flora of the period consisted of ferns, 

 cycads, and conifers; zosterse flourished in the ponds 

 and morasses. The zosteras are monocotyledonous 

 plants of the family of the Naiadacese, wliich thrive in 

 the sandy mud of maritime or littoral regions, and form, 

 with their long, narrow, and ribbon-like leaves, vast 

 prairies of emerald green. These masses of verdure 

 appear partly exposed at low tide, and provide nourish- 

 ment and an asylum for numerous marine animals. 



At Portland, on the Dorsetshire coast, the character- 

 istics of the Oolitic vegetation may be examined by the 

 student with peculiar facility. Its quarries reveal in 

 section the strata of the primeval world. On the well- 

 known Portland stone rests a bed of limestone formed 

 in lacustrine waters; and on this bed another, of a dark 

 bluish substance, which, on examination, is found to be 

 a well-preserved vegetable earth or humus, resembling 

 our vegetable soil, from fifteen to eighteen inches thick, 

 and abounding in the silicified remains of conifers and 

 other plants, analogous to the Zamia and Cycas. Herein 

 the trunks of great numbers of silicilred trees and tropi- 

 cal plants are found, standing erect, their roots struck 

 deep into the soil. 



" The ruins of a forest upou the ruins of a sea," says 



Esquiros, " the trunks of these trees were petrified while 

 still growing. The region now occupied by the narrow 

 channel and its environs had been at first a sea, in 

 whose bed the Oolitic deposits which now form the 

 Portland stone accumulated : the bed of the sea gradu- 

 ally rose and emerged from the waves. Upon the land 

 thus rescued from the deep, plants began to grow; they 

 now constitute with their ruins the soil of the dirt-bed. 

 This soil, with its forest of trees, was afterwards plunged 

 again into the waters — not the bitter waters of the 

 ocean, but in the fresh waters of a lake formed at the 

 mouth of some great river." 



We may now turn to our ideal landscape. 



Amongthe tree-ferns we recognize the Splienophyllum 

 as still predominant in this vegetation, and investing it 

 with an air of peculiar elegance. 



No palms are visible, but in their place spring the 

 tall stems of the pandanas, the zamites, and the 

 branching conifers. 



A coral islet rising above the azure waves, like a 

 Polynesian atoll, reminds us of the importance now 

 assumed by the labours of the coralline animals, which 

 have ever played so conspicuous a part in the creation 

 of our modern globe. 



The animals represented are the Crocodikinus, the 

 Itami^horynchus, and certain invertebrata, such as the 

 Astoria, Comatula, Ilemicidaris, Pteroceras. In the 

 genial air Hies the bird of Soleuhofen, the Archa>op- 

 teryx* which has been reconstructed from the skele- 

 ton; the head, however, has not been discovered. The 

 footprints on the sand may be those of the rampho- 

 ryncbus, or, perhaps, of the pterodactyle (Plate C). 



We now proceed to a consideration of the types of 

 organic life peculiar to the Cretaceous period. 



THE CEETACEOUS PEraOD. 



The strata of the Cretaceous period, or the Chalk 

 formations, form the upper strata of the Secondary 

 series ; and while resting upon the Oolite, are them- 

 selves the base of the Tertiary or more recent beds. 

 They cover an extended area in Europe and the east 

 of Asia, and have also been found in North and South 

 America. In the south-east of England they occur 

 in those rounded and grassy downs which are so char- 

 acteristic a feature of Kent, Surrey, Sussex, Hamp- 

 shire, Dorsetshire, and the Isle of Wight, and stretching 

 along the coast in a line of lofty and glittering cliffs, 

 to which England owes her ancient name of A Ihion. 

 These beds are connected with similar beds in Den- 

 mark, Germany, and the north of France ; and it is 

 surmised, from the masses of chalk and flint thrown 

 upon the shores of the Shetland Isles after a storm, 

 that the bed of the German Ocean is composed of the 

 rocks of this formation. 



The strata are arranged by most geologists in the 

 following order : — 



UPPEK. 



Maestriclit, 

 Clialk with flints, 

 ClKilk witliout flints, . 

 Cliulk inai-l, 

 Upper giecnsand, 



* See page 25. 



Maximum Thick- 

 ne33 in Feet. 



. 100 



. 500 



. GOO 



. 100 



. 100 



