136 On the Tchormi Zem. 



become covered with fine silt or mud, such as we know, from the 

 soundincrs of hydrographers, is often found beneath mediterranean 

 waters, far removed from the action of currents. 



The absence of any marine shells in this fine sediment is, it is 

 true, a negative fact, which, if unaccompanied by some explana- 

 tion, might indispose my readers to admit this hypothesis. We 

 must, however, bear in mind that, after their emersion, the 

 central parts of Russia, if but slowly and slightly elevated, 

 may have long remained in an intermediate state of mire or 

 slough with little egress for water ; so that the remains of deli- 

 cate testacea (if they existed) may have been entirely decom- 

 posed by the alternations of aqueous and atmospheric agency. 

 But whether we adopt this view or not, we cannot, I repeat, look 

 at the very great uniformity of its composition over such vast 

 tracts, and its independence of existing drainage, without rejecting 

 any theory Avhich would account for the production of the 

 " Tchornoi Zem " by subaerial causes only, and on these grounds 

 w^e must, I think, account for its origin by aqueous deposit and 

 the subsequent modifications which it underwent in passing into 

 a terrestrial condition. 



Lastly, 1 am borne out in this inference by the black colour of 

 the soil ; for whilst the eminent chemists above cited ha\'e ascer- 

 tained that soils of very different external appearance are nearly 

 identical in their analysis with the black earth of Russia, the re- 

 maining difference, or that of colour, may be due in the English 

 and French examples to the vegetable matter being less decom- 

 posed than in the case of the "Tchornoi Zem," an argument I 

 beg leave to adduce as an additional proof of the materials having 

 been originally deposited under water. 



XII. — Lecttire on the Application of Science to Agriculture. 

 Delivered before the Members of the Royal Agricultural 

 Society of England, on Thursday the 9th of December, 1841. 

 By Charles Daubeny, M.D., F.R.S., Hon. Mem. of the 

 R. E. Agricultural Society, Vice-President of the Geological 

 Society, and Professor of Rural Economy in the University 

 of Oxford. 



In acceding to the request made to me a few days ago on the 

 part of the Council of the Royal Agricultural Society through 

 their President, and attempting, in conformity with their wishes, 

 to deliver before the farmers now assembled in the miCtropolis a 

 lecture on some subject connected with the class of pursuits 



