SO PROCEEDINGS OF WASHINGTON MEETING. 



hi discussing the paper, Professor E. \V. Hilgard spoke as follows: 



I have been greatly interested in Professor Krassnof's paper, as I have studied 

 the American "black-prairie soils'" in considerable detail; and, on the whole, I 

 agree entirely with him in his conclusions as to the conditions under which such 

 soils may he formed. There is one conclusion, however, which he has only casually 

 mentioned, yet which is, according to my investigations, a conditio sim qua non. I 

 refer to the neutrality of the "black earths" as compared with the decided acidity of 

 peaty soils. The cause of this neutrality is the presence of at least a certain mini- 

 mum amount of calcic carbonate; and in its absence 1 think such soils cannot be 

 formed. The fact mentioned by him, that the chernozem occurs in the main in 

 the loess region only, assures me that the same condition is fulfilled in Russia. All 

 the " black-prairie " soils I have studied in this country are essentially calcareous 

 soils, usually overlying limestones or marly rock-, or. in the case of drift areas, cal- 

 careous gravels. The eminent usefulness of lime in soils is well understood, and 

 those in which it and the abundant products of organic decomposition are com- 

 bined might naturally be expected to he profusely fertile ; and this is notoriously 

 true of our prairie soils, as well as of the Russian "black earth" — it is as true in 

 California, where such soils are now in process of formal ion. as it is of the prairies 

 of the west. 



I have heretofore inferred the calcareous nature of the chernozem from analyses 

 communicated to me by Professor Grandeau ; 1 am pleased to have the fact con- 

 firmed by Professor Krassnof. I do not, however, wish to be understood as assert- 

 ing that calcic carbonate alone can produce such soils without other concurrent 

 conditions, such as were mentioned in the paper, nor that such soils must neces- 

 sarily be effervescent with acids. All the essential effects of lime in soils are assured 

 by the presence of one or two percent of the carbonate, or even le>s ; which amounts, 

 when finely diffused, will not usually show effervescence with any degree of cer- 

 tainty, but suffice to produce characteristic lime vegetation, and to guide the held 

 geologist in the outlining of calcareous areas. 



I cannot but express also my gratification at having these latest of geological for- 

 mations — the soils — introduced into the discussions of this Society. Their economic 

 importance certainly justifies it. but thus far their consideration ha- usually been 

 relegated to the chemical or agricultural societies alone. 



Professor (i. ('. Broadhead said : 



Never having had the pleasure of visiting southern Russia, I cannot, of course, 

 say anything of the region spoken of in so interestinga manner by Professor Krass- 

 nof; but some time ago I was interested in the "black earth" of those steppes 

 described in a volume of RSclus. I was forcibly struck with the resemblance to 

 our own " black-prairie soils." Now, I do not say that in certain regions these soils 

 cannot be found, but my own observation goes to show that there are well-marked 

 and extensive areas of such in the states of Illinois, Missouri and Kansas. In Illi- 

 nois the " black soil" covers the greater part of the counties of Moultrie, Macon 

 and Piatt, resting on either the drift or else the upper < !oal Measures. In Missouri 

 the "black soil" is found in Saline county, resting on beds of the lower Coal 

 Measures. Further westward in Missouri, in the counties of Cass and Jackson, 

 it rests upon the rocks of the upper Coal Measures. It is also well developed in 

 northwestern Missouri, where it lies upon the drift or else directly on rocks of 



