168 GLOLOGY. 
claws, and full-spread plumage are finely seen. The remains of the 
earliest warm-blooded animals have also been found—a kind of pouched 
creature like the kangaroo. 
Scenery.—The scenery and animals of the Oolitic Period resemble, to 
a remarkable extent, those of Australia, both in vegetable and animal 
remains, The land and water went through many changes during this long 
period. In the, Lias times, the seas were deep and tranquil; under the 
Oolite, exp coral beaches were dashed by great breakers, that have 
left their work in broken shells and marls; while the Wealden seems to 
have been the carried deposits laid down in the estuary of a mighty river, 
that rolled into the sea in what is now the south of England; and the 
present icy lands of the arctic regions were covered with the vegetation 
of a warm cham which now appears as Oolitic coal strata. 
X.—Chalk or Cretaceous System. 
Immediately above the Oolite lies a system in which the chief rock is 
the well-known substance chalk, and which has hence received the name 
of the Chalk, or, what is the same thing, Cretaceous! System. In this system, 
other rocks also occur, chalk-marl or blue-clay, known by the local name 
of Gault or Golt; thick beds of green-coloured sand, called Greensand ; 
and, embedded in the chalk, nodules of flint, which when less pure is 
called Chert; and coal, in Vancouver’s Island. The chalk is used for 
many purposes: when it is burned, it forms a useful lime ; when hard 
enough, is used for building-stone ; and when crystallised, forms a fine 
white marble. The flints are an important ingredient in china, porcelain, 
and glass, and from the sands we obtain fuller’s-earth. The whole system 
has been ‘generally divided into two groups, the lower being called the 
Greensand, and the upper the Chalk. 
Organic Remains.—The plant-remains are rare and imperfect, and seem 
to have been all drifted. Leaves of different kinds, palms, fruits, cones, 
and bits of pines have been discovered. Animal remains, however, are 
very numerous, and most beautifully preserved. We find sponges, corals, 
sea-urchins, complete in form and structure, beautiful star-fish, numerous 
crustaceans, and varieties of the lobster tribe. The shells are plentiful, 
and eetisitely beautiful in form and even in colouring, and are 
the finest fossil preservations found in any system—ineluding splendid 
ammonites and nautiluses, and hundreds of other species, whose mere 
names would fill pages. Fishes are not numerous, but are well preserved, 
and, as in other systems, are named from peculiarities 1 in form or structure, 
such as the ‘twisted tooth, the narinkle tooth,’ ‘thick tooth,’ and such 
y 
1 From tasty ercta, chalk. 
ed 
