THE MICROSCOPE IN GEOLOGY. 1 09 



Williamson have shown that not only are there multi- 

 tudes of minute remains of living organisms, both 

 animal and vegetable, but that it is entirely, or almost 

 wholly, composed of such remains. Amongst these 

 were about twenty-six species of Diatomaceae (sili- 

 ceous), eight species of Foraminifera (calcareous), and 

 a miscellaneous group of objects, consisting of calca- 

 reous and siliceous spicules of sponges and Gorgoniae, 

 and ot fragments of the calcareous skeletons of echi- 

 noderms and mollusks. The deep-sea soundings which 

 have recently been obtained from various parts of the 

 ocean-bed afford results more or less similar; the variety 

 of form, however, usually showing a diminution as the 

 depth increases. From an extensive comparison of 

 the forms of recent Foraminifera brought up from dit- 

 ferent depths, Messrs. Parker and Rupert Jones con- 

 sider themselves able to predicate the range of depth 

 within which any particular collection may have been 

 taken ; and thus to determine, in the case of deposits 

 of fossil Foraminifera, within what range of depth they 

 were probably formed."* 



Very interesting results have attended the various 

 deep-sea expeditions that have taken place the last 

 few years in different parts of the Atlantic. It has 

 been estimated that nearly two hundredweight of the 

 sea-bottom, revealing, contrary to preconceived notions, 

 a submarine life at a depth of more than 2,000 fathoms, 

 has been dredged up and examined. One of the 

 most curious questions relates to the deposits in the 

 deep water of the Atlantic, and their connection with 

 the Cretaceous period of geologists. For very many 

 years the origin of chalk has been a point of discus- 

 sion. If you will rub a bit of whiting in a drop ot" 

 water on a glass side, cover with thin glass, and use a 



* Carpenter on the Microscope, p. 755. 



