54 POPULAE ILLUSTRATIONS OF 



altogether a great increase in the number of species in at least three 

 out of four of the classes I have mentioned in the Neozoic period. 

 But they not only increase in number, but in diversity and character. 

 Thus, any one seeing a Paleozoic fish or reptile, who is acquainted 

 with the subject, would recognise it from any part of the world as 

 such, but he would have a difficulty in separating those found in one 

 part of the world from those found in another ; whereas, as Professor 

 Haughton remarks, " in the Neozoic period each bed of rocks and, 

 I may add, each particular country, has its peculiar and characteristic 

 fossils, which are easily distinguished from fossils of other parts of 

 the earth formed during the same time." 



With the Foraminifera, however, there has been but little change 

 in time. Messrs. Rupert Jones and Parker have described a bed of 

 clay at Chellaston as being almost entirely formed by the genus 

 Eotalia. This clay belongs to the Upper Trias, and we have just 

 seen that the Eotalia were associated with the Fusulina in forming 

 the Russian limestone in the Coal period. The same shells are 

 found in the Jurassic and Cretaceous systems, and are very abundant 

 in the crag on the Essex and Suffolk coasts. My figures were from 

 species existing in our own seas. The genus Bulimina is also found 

 in the Upper Trias and all subsequent strata. It occurs abundantly 

 in our seas, and I figured recent species of it in the last chapter 

 (Fig. 58, p. 42). 



It is, however, in the Cretaceous group of strata that the Fora- 

 minifera begin to appear most abundantly. It may surprise many of 

 my readers when I tell them that the chalk cliffs throughout the 

 world consist mainly of the remains of Foraminifera. We cannot go 

 when we will and examine the stupendous Laurentian rocks, but we 

 can visit our chalk cliffs at Dover, or wander over our Sussex downs ; 

 and we can also realise the great use to man of chalk, when we see 

 our farmers spreading it upon their stiff clays ; and we can without 

 much trouble follow the " white hills " into Ireland and Spain, 

 France and Greece, for an extent of 1140 miles. We can follow 

 them from the south of Sweden to Bordeaux for 840 miles, and we 

 can measure these cliffs, and find them to have a thickness of from 

 600 to 1000 feet ; and then we can sit down in some snug corner, 

 and smoke our pipes, and ponder upon the wonderful fact that all 

 the most important parts of our earth's crust have been built up 

 by an animal, sometimes so small as only to be seen through the 

 microscope a creature without muscle, bone, nerve, or blood vessel 

 a mere lump of jelly ! 



But our inquiry is not yet over, for we have been into Egypt and 

 seen the Pyramids. "What of that?" I can fancy I hear one of 

 those sceptics, who never will see anything in anything, cry out, 



