394 Scientific Intelligence — Zoology. 



Professor Ehrenherg. — The Tchornoi Zem, or Black Earth of cen- 

 tral Russia, covering more than 60,000 geographical square miles, 

 and of extreme fertility, supporting more than 20,000,000 of souls, 

 and giving rise to an annual exportation of about 20,000,000 hecto- 

 litres (55,000,000 bushels) of cereals, was described by Sir R. I. 

 Murchison in 1842,* and was considered by him to be a submarine 

 deposit, accumulated in quiet water, and possibly of nearly the same 

 age as the Loess of the Rhine. M. Ehrenberg, on examining the 

 Black Earth under the microscope, found in it six forms of Poly- 

 gastrica, and twenty- two of Phytolitharia ; and concludes that it is 

 not an aqueous deposit, but rather a soil formed of the debris of 

 ancient forests — an origin hypothetically givenf to this peculiar for- 

 mation by earlier observers. — Quarterly Journal of the Geological 

 Society, vol. vii.. No. 27, p. 112. 



4. Outlines of Continents not Fixed. — The outlines of continents 

 are not to be considered as fixed, immovable limits, but are variable, 

 and dependent upon the degree of elevation above the level of the 

 sea. For instance, were we to depress certain parts of South 

 America, or of the United States, even for a few feet, their outlines 

 would be entirely changed, and immense tracts submerged, and vice 

 versa, a slight elevation would produce corresponding changes. 



The west of Asia, comprising Palestine and the country about 

 Ararat and the Caspian Sea, &c., is below the level of the ocean, 

 and a rent in the mountain chains by which it is surrounded would 

 transform it into a vast gulf. 



Continents are in fact only a patch work formed by the emer- 

 gence and subsidence of land. These processes are still going on 

 in various parts of the globe. Where the shores of the continent 

 are abrupt and high, the effect produced may be slight ; as in Norway 

 and Sweden, where a gradual elevation is now going on without 

 much alteration of their outlines. But if the continent of North 

 America were to be depressed a thousand feet, nothing would remain 

 of it except a few islands ; and any elevation would add vast tracts 

 to its shores. — Agassiz on Lake Superior, p. 96. 



ZOOLOGY. 



5. Gypsies of Great Britain. — Now look at the gypsies of Great 

 Britain. They are wanderers without fixed habitations ; whilst, at 

 the same time, they are more abundant in some parts of the island 

 than others. They have no very definite occupation ; yet they are 

 oftener tinkers and tinman than aught else equally legal. They in- 

 termarry with the English but little. All this is caste, although we 

 may not exactly call it so. Then, again, they have a peculiar lan- 

 guage, although it is so imperfectly known to the majority of the 



* Proc. Geol. Soc., vol. iii., pp. 712, efseg-. ,• and Geol. Russia, Vol. i., p. 557. 

 t Loc. cit., p. 714. 



