PLANTS OP NORTHERN OUJARAT. 
218 
Department. Both these depressions contain deep and shifting ooze, 
consisting of very fine clay particles. The Harsol Tank Chain is a 
series of shallow tanks, which are liable to dry, some every year and 
others only in years of deficient rainfall. Besides these, there are other 
smaller depressions and tanks. 
It is not to be supposed that this sand region is entirely flat. On 
the contrary the land rises and falls slightly in most places, while at 
many points definite hills occur where the sand is harder and more 
coagulated. 
Wherever there is an outlet for storm water, the sand denudes with 
amazing rapidity. The banks of the rivers and streams in the sand area 
are complicated by a network of small canon-like nallahs, called 
" wanghas ** in the vernacular, which further ramify and extend with 
each succeeding monsoon. Villages on the banks of these rivers are 
constantly compelled to remove further inland. 
Within the sand area there are three types of aberrant soil, viz. : — 
(1) uplands of darker soil, which constantly subsides in small waterholes 
varying from one to ten feet broad and one to four feet deep ; these lands 
are covered with stretches of magnificent fodder grasses, the association 
of which will be discussed more fully below,* — (2) valleys of salt- 
encrusted loam, on which the vegetation is very scanty, the only grasses 
being dwarf forms such as Chi oris villosa , etc., — and (3) an entirely 
isolated plateau or upland between Talod and Harsol formed by an out- 
crop of red laterite. This abnormal geological formation is marked by 
a fair number of species which do not occur elsewhere in our area but are 
found on laterite in other parts of the Presidency. The top of this 
plateau is a clay layer of varying depth liable to subside in water holes as 
described under (1) above. 
East of the Majam R. the conditions change, black soil becoming 
frequent, especially in the south, and stony hills, especially in the north. 
In the west and south of this area, which is thinly populated, are vast 
stretches of Savannah, dominated by stunted trees, seldom above twelve 
feet high, of Butca frondosa . But by the time Modasa is reached, 
xerophytio woodland has begun to appear, characterised at first by 
stunted teak, then by Sterculia urens and lastly by Terrninalia 
tomentosa. As would be expected, the beds of the Majam and the 
Watrak are rocky, and their floras, and especially that of the Watrak, 
differ essentially from the floras of the rivers in the sand area. 
Kharaghoda stands somewhat apart from the rest of the country 
worked. But it is desirable t^ include it, both because otherwise many 
# S^e Part II, Sec. VI, pp. 232-283. 
