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of Zeno's reasoning, ridiculed by Cicero: “If well-tuned pipes 
are formed out of the olive-tree, is it to be doubted that there 
is an innate skill of piping in the olive-tree itself? ” * 
34. Chalk . — The ooze at the bottom of the Atlantic, as 
examined by the nautical explorers in 1858, and by the dredging 
expedition in 1869, contains a multitude of foraminiferous 
creatures (globigerinse) mingled with fragments of diatoms and 
sponges. This occurs more especially in the course of warm 
currents. These are interspersed with colder spaces floored with 
sand, and less marked by organic life. These deposits are analo- 
gous alike to the chalk and to older shales and sediments. They 
are the present representatives of beds common in the geological 
periods, and specially manifested in the white chalk. The latter 
is found in borings at great depths, and also at heights 10,000 
feet above the present sea-level. The Atlantic formation is 
increasing at a rate hardly appreciable ; it is undergoing drift- 
ing and re-sorting by change of currents ; thus bringing it into 
analogy with the old deposits. But the amount of fine cal- 
careous sediment of one description, accumulated and spread 
out in the upper chalk formation, upwards of 1,000 feet thick, 
extending from Sweden to Spain, and from Ireland to the 
Black Sea, is so enormously in excess of any modern operation, 
that the latter cannot be considered as a return to the cretaceous 
cycle, but merely as an instance of the feebler action of similar 
causes. If the Atlantic sea-bed were so deep as to afford space 
for the accumulation of 1,000 feet of foraminiferous marl, and if 
the whole were then lifted up with the sands, clays, and gravels 
of the base to form a land-surface, and then again lowered so 
deep as to form a bed for the tertiary marine formations, — that 
is to say, if something quite imaginable but not at all observed, 
were to occur, then the conclusion would be correct that chalk 
was recurrent or continuous. The Atlantic ooze certainly forms 
imperfect oolite and imperfect chalk, just as bog-iron forms 
imperfect iron-bands, and peat imperfect coal-beds; but it is 
obvious that the chalk will continue to maintain its title to be 
considered as the leading product at one period, just as the 
others were the characteristic products at other .stages of the 
great progress. 
35. The Tertiary formations might be supposed to yield the 
most obvious proofs of recurrence or evolution, if either of 
these is a true theory. Yet when we examine them ever so 
slightly we are led to opposite conclusions. Consider the 
tertiaries underneath London. We have first an estuary de- 
posit of pale-coloured sands and clays called the Woolwich beds, 
* Cicero, De Natura Deorum, book ii. 
