ALLUVIUM. RECENT FORMATIONS. 767 



and may be granted in this place as a matter of convenience. It occurs therefore at the 

 head of this chapter as a general title for those superficial formations which appear to 

 have transpired since our planet received its present configuration of land and sea, and 

 Man became its occupant and master, which are now in course of production, whether 

 due to aqueous, igneous, atmospheric, organic, or human agency, the effects of one or of 

 several of these causes combined. In some of these recent aggregations we meet with the 

 remains of man and contemporaneous animals and plants, with human utensils and orna 

 ments also, characteristic of the ancient British age in our own country, the Etruscan 

 in Italy, the Pelasgic in Greece, and the era of the Pharaohs along the banks of the Nile. 

 But we discover no bones that can be specifically identified as those of the great quadru 

 peds of the drift, which probably mostly perished in those physical changes under which 

 it accumulated, subsequent to which the present state of things commenced, and man, with 

 the existing animal races, was created. Some have supposed, indeed, that America had 

 its droves of mastodons and megatheridas browsing upon its savannahs down to a compa 

 ratively modern period ; and good evidence supports the idea, that the gigantic horned 

 elk continued to be an inhabitant of Europe coexistent with the human race. Such con 

 clusions, supposing them to be established, are in harmony with the views already 

 expressed respecting the first appearance of the present animal races as produced around 

 several centres of creation, not contemporaneously, our sacred history dealing merely 

 with one of those districts, the most recent, that in which the primitive man was 

 placed. There is no difficulty in conceiving of the extinction of some tribes of animals as 

 the consequence of current events ; such as one of those unusually long droughts to 

 which South America is occasionally subject, when, as during the gran seco, which lasted 

 three successive years, it was calculated that from a million and a half to two millions of 

 animals died exhausted by hunger, the borders of all the lakes and streamlets in the pro 

 vince of Buenos Ayres being long aftei'wards white with their bones. The case of the 

 dodo, a large and remarkable bird existing in the Mauritius during the early voyages to 

 the East, appears to be a well-authenticated instance of the death of a species in compa 

 ratively recent times ; and now of several races dangerous to man, or usefu! to him for 

 their skins, it may be predicated that the period of their extinction is not very distant. 



Of formations contemporaneous with the present era, an arrangement may be adopted 

 which classifies them according to the agency immediately operating in their production. 



1. Organic coral reefs; peat-mosses or bogs ; subterranean forests. 



Formations of coral the agglutinated skeletons of departed races of coral zoophytes, 

 composed of carbonate of lime secreted from the ocean, with broken shells, echinites, and 

 sand, all cemented together into hard calcareous rock are among the most interesting 

 organic constructions of modern as of ancient times, now in course of augmentation from 

 the living swarms. Detail here will be unnecessary, having previously referred at large 

 to the islands which owe their origin to these marvellous creatures ; and also to the sub 

 merged reefs advancing surely towards the surface of the waters, though at an excessively 

 slow rate to us, which a slight submarine eruption might elevate into chains and clusters 

 of islets, the agency undoubtedly which has uplifted some of the coralline formations of 

 the Pacific thousands of feet above the deep. The island of Tahiti, composed almost 

 entirely of volcanic rocks, has on the summit of its highest mountain a coralline stratum ; 

 a similar bed occurs in the Isle of France, between two lava currents ; and all voyagers 

 of modern date Beechey, Quoy and Gaimard, Stutchberry, and Darwin concur in 

 the opinion that the coral reefs and islands proceeding in the Pacific do not go down 

 many hundred feet below the surface of the waves, but rest upon submarine volcanic 

 ridges and rocks. The cut in the next page represents species of three common genera 

 of corals : Caryophyllia, the external character of the polyparium or stony skeleton of 



