CHALK MAKERS, OR FORAMINIFERA. 53 



know of no fact inconsistent with the view, which 

 Professor Wyville Thomson has advocated, that the 

 modern chalk is not only the lineal descendant, so to- 

 speak, of the ancient chalk, but that it remains in 

 possession of the ancestral estate ; and that from the 

 cretaceous period (if not earlier) to the present day 

 the deep sea has covered a large part of what is now 

 the area of the Atlantic." 



Accepting, therefore, this doctrine of the continuity 

 of the chalk, and, consequently, its intimate relation- 

 ship with our subject, let us endeavour to make some 

 slight acquaintance with the microscopical characters 

 of the common Kentish chalk. In order to do so,, 

 some little preparation is necessary. Take a small 

 quantity of chalk in powder, say, two ounces, and 

 place it in a glass bottle holding about a quart. 

 Water is poured in upon the chalk until the bottle is- 

 nearly full. The whole is then shaken up, when it 

 resembles milk in colour and consistency, and placed 

 in some position where it remains undisturbed for 

 half an hour. The heavier particles will have sunk 

 to the bottom, the lighter remain suspended in the 

 water, which latter is drawn off, and fresh clear water 

 added, then the bottle may be -stood aside to settle 

 as before. This process is repeated again and again 

 until the water is no longer turbid, after standing for 

 a few minutes. The sediment, or deposit, at the 

 bottom of the' bottle will be found to be very much 



