in.] THE STONES IN THE WALL. 85 



known to the unknown, from the Atlantic deep-sea 

 ooze which we do know about, to the chalk which 

 we do not know about, the whole of the chalk must 

 have been laid down at the bottom of a deep and still 

 ocean, far out of the reach of winds, tides, and even 

 currents, as a great part of the Atlantic sea-floor is at 

 this day. 



Prodigious ! says the reader. And so it is. 

 Prodigious to think that that shallow Greensand 

 shore, strewed with dead animals, should sink to the 

 bottom of an ocean, perhaps a mile, perhaps some 

 four miles deep. Prodigious the time during which it 

 must have lain as a still ocean-floor. For so minute 

 are the living atomies which form the ooze, that an 

 inch, I should say, is as much as we can allow for their 

 yearly deposit ; and the chalk is at least a thousand 

 feet thick. It may have taken, therefore, twelve 

 thousand years to form the chalk alone. A rough 

 guess, of course, but one as likely to be two or three 

 times too little as two or three times too big. Such, 

 or somewhat such, is the fact. It had long been 

 suspected, and more than suspected; and the late 

 discoveries of Dr. Carpenter and Mr. Wy ville Thompson 

 have surely placed it beyond doubt. 



Thus, surely, if we call the Oolitic beds one new 

 world above the New Red sandstone, we must call the 

 chalk a second new world in like wise. 



I will not trouble the reader here with the reasons 

 why geologists connect the chalk with the greensands 

 below it, by regular gradations, in spite of the enormous 

 downward leap, from sea-shore to deep ocean, which 

 the beds seem (but only seem) to have taken. The 

 change like all changes in geology was probably 



