196 NUMMULITES AND MOUNTAINS. 



probably much greater than is compatible with the physical 

 conditions of the globe. This hypothesis may, therefore, 

 be dismissed as untenable ; more especially as there is 

 direct evidence of a totally different kind, which is 

 conclusive as to the truth of the alternative view. 



This evidence is afforded by fossils, and more especially 

 by a particular kind of fossil, which, from its abundance 

 and the restricted geological epoch in which it is found in 

 any quantities, is of more than usual value in inquiries 

 of the present nature. 



If any of our readers have ever examined the Tertiary 

 clays and sands of Barton, in Hampshire, or of Brackle- 

 sham, on the Sussex coast, they will probably have met 

 with numerous disc-like objects, the larger of which are 

 somewhat more than an inch in diameter, while the 

 smallest are scarcely bigger than a pin's head. When 

 split or cut, these objects are found to contain a number 

 of minute chambers, separated from one another by thin 

 walls arranged in the form of a spiral, as shown in the 

 figure. Technically they are known as nummulites, and 

 belong to the very lowest division of the animal kingdom 

 lower even than the sponges, which some people cannot 

 be persuaded to believe are animals at all. Now these 

 nummulites are exceedingly interesting to those who study 

 the growth and formation of mountain ranges for the 

 reason that they occur, in any quantity and of large size, 

 only through the greater portion of the Eocene or lowest 

 division of the Tertiary (latest) geological period, although 

 not reaching down to the London clay ; and also because 

 they were very widely distributed in the seas which then 

 covered a large part of our existing continents. If, then, 

 we should find rocks containing great numbers of large 

 nummulites on the flanks or tops of a mountain range, we 

 should be assured that such range was younger than the 

 Eocene period, at which date its component rocks were 

 being formed as mud at the bottom of the sea. 



Now, although in England the aforesaid nummulites 

 only occur in soft beds of clay and sand in the low cliffs 

 of the southern coast, when we cross to the Continent we 

 find them forming the greater part of a massive limestone, 



