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all such areas known to him were characterized by essentially 
horizontal strata, level surfaces, and finely divided soil. He 
distinguished between cause and effect, unlike some others who 
have written on the subject, but admitted his inability to show 
a causal relation between the conditions he described and the 
absence of trees. What he said about the topography and soil 
of the western prairies applies almost as well to those of Long 
Island* (which he probably knew nothing about), and even to 
some other kinds of treeless areas, such as wet meadows and salt 
marshes. 
Although the prairies of Long Island are closely correlated with 
a certain type of soil, it is still an open question whether most of 
Fic. 7. Looking up East Meadow Brook from the Farmingdale Road, running 
east from Hempstead. Aug. 25, 1909. 
the peculiarities of prairie soil, here and elsewhere, may not be 
due to long occupation of the same ground by herbaceous vege- 
tation. In its mechanical analysis, and even in its color, the 
“Hempstead loam” strikingly resembles the “ Galveston clay” 
(an arbitrary name for a well-known type of soil, the salt marsh) 
described in the same government soil report; but it is probably 
* Mechanical analyses of the “Hempstead loam” by the U. S. Soil Survey show 
that about 76 per cent of it consists of particles less than 1/20 of a millimeter in 
diameter, and that less than 3 per cent of it is in particles exceeding a millimeter. 
