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HOW SCENERY IS MADE. 
V. — Origin of Limestone Rocks. 
T is the general belief of geologists that all limestone 
rocks, of any large extent, take their origin from the 
dead shells, &c., of marine organisms of various kinds. 
Thus, chalk was originally — as it is even now being 
formed at the bottom of the Atlantic Ocean — composed of 
the microscopic shells of creatures called Foraminifera. These 
live in the upper parts of the sea ; but when dead, the shells 
sink to the bottom, forming a soft white “ ooze.” When this 
sea-bottom is elevated and makes a land surface, flat or rounded 
and undulating hilly scenery is the final result after denu- 
dation by rain ; as, having no depth of soil, it is devoid of trees. 
Such are the North and South Downs, Salisbury Plain, &c. 
Limestones are of various kinds as far as their composition is 
concerned. Thus many are “ coralline,” i.e. they have resulted 
from enormous growths of corals, which, by continually dying 
and becoming decomposed, form masses of stony matter, in which 
remains of corals still exist. Such limestone occurs at Malton, 
near Scarborough, and in Devonshire, where the rock is hard 
enough to take a fine polish, constituting marble. This is much 
used for mantelpieces. In Derbyshire the limestone abounds 
with fossil “ encrinites,” a sort of stalked starfish, and is full of 
the broken joints of the stems. This, also, forms a good 
marble much used in Derbyshire. When rendered black by the 
presence of carbonaceous matter, it is used for small ornaments 
often inlaid with malachite. Plymouth is paved with marble. 
Coralline limestone is still in course of formation round 
tropical islands of the Pacific Ocean, and off the coast of 
Australia, &c. 
If a limestone happens to be in a volcanic country and 
subjected to great heat, it becomes crystallised and forms 
“ statuary marble,” which, when broken, resembles crystalline 
loaf-sugar. This kind is seen in the familiar tops of wash- 
handstands, mantelpieces, &c. It comes from Italy and Greece. 
The limestone of Egypt, of which the pyramids are built, is 
remarkable for looking as if it was filled with pieces of money 
made of stone. These are enormous kinds of foraminifera, 
whilst those of the chalk are microscopical, and therefore not 
distinguishable with the naked eye. It is called nummulitic 
limestone, from the latin word nummus, meaning “ money.” 
As the presence of nummulitic limestone has been detected 
high up in the Alps and Himalaya Mountains, and nummulites 
occur in the clays of Bognor in England, this proves that the 
great range of mountains running east and west from the 
Pyrenees to the Island of Formosa have been upheaved in a 
comparatively {i.e. geologically speaking) late period of the 
