238 



PICTURESQUE SKETCHES 



sions perfectly microscopic, and absolutely invisible to 

 the naked eye, to about the bigness of a five-shilling 

 piece. In shape their habitation is sometimes flat 

 and disc-like, resembling a piece of money, and some- 

 times it presents the most singular modifications of 

 form, including every variety that can be conceived 

 to arise from the indiscriminate heaping together of a 

 great number of very differently shaped chambers, as 

 unlike one another in size as they are in shape. 



Animals of this low organization multiply rapidly, 

 and are capable of making very important geological 

 deposits. While, indeed, the vertebrated animals 

 and the larger and more complicated mollusks live 

 for some considerable time, and modify during that 

 time the general conditions of organic existence, these 

 little creatures the coral animal, the animalcule, and 

 the Foraminifera may, by their rapid secretion of 

 solid matter from the water, and (owing to their 

 brief existence) equally rapid deposition of it in a 

 solid form, lay the foundation of islands, and even of 

 new continents. The land thus formed may, when 

 brought above the sea level, be destined to last, with 

 little change, throughout many successive geological 

 epochs, during which group after group of species of 

 the higher animals may be introduced and destroyed, 

 some of which leave no indication of their ever having 

 existed, while others are represented by a few bones, 

 a tooth, a scale, or perhaps only by the faint impress 

 of a footstep. 



How important, then, it becomes that we should 

 understand these, the common hieroglyphics, even if 

 their meaning is less full, and when they talk an ear- 

 lier and a simpler language than the others, since the 

 sacred characters which speak of higher events are so 



