THE EOMANCE OF NATURAL HISTORY. 



cies present. ... I have been enabled to examine 

 some of the curious raised fossil beach near Copi- 

 apo in Chili, which is gradually forming into stone. 

 Though this beach is one mile from the present 

 shore, and 180 feet above the level of the sea, yet 

 I have found in it diatoms of the same species as 

 those that occur on the shore at the present day ; 

 the diatoms are also found in a fossil state in peat, 

 coal, bog iron-ore, flint, and the chalk formation. 

 Thus, in a geological view, though individually 

 invisible, yet numerically they perform a most im- 

 portant part in the crust of the earth — a part 

 more important than all the mighty monsters 



that lived in ages past What purpose do 



these bodies serve? It is highly possible that they 

 form, in a great measure, the food of all the minor 

 aquatic animals more highly organised than them- 

 selves ; I have often found, on examining shrimps, 

 that their stomachs, which are situated behind 

 the eyes, are entirely filled with diatoms.. That 

 the siliceous shell passes through nearly intact, 

 there can be no doubt, but it is certain that the 

 internal structure, the endochrome, may be di- 

 gested and form the nutritive portion; in this 

 view I am borne out by referring to guano — a 

 most prolific source of fossil diatoms. Here we 

 find abundance of siliceous shells, in fact their 

 presence or absence is now the test of the genuine- 

 ness of the article ; — these, in past ages, must have 

 been consumed by small marine animals, these 

 again consumed by fish, and these in their turn by 

 birds : in guano I have noticed the proportion of 

 diatoms to be in some specimens nearly 1 in 500 

 parts. A correspondent from Callao, writing to 

 the Illustrated London News, on the Cincha 

 guano islands, says the export of guano from the 

 islands has increased considerably during the last 

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