170 
Records of the. Geological Survey of India. 
[vOL. X, 
In the Jaipur-Bustar plateau, which has an average elevation of about 1,800 feet, laterite, 
though perhaps of inconsiderable thickness, is very widespread, often completely conceal¬ 
ing the underlying rocks over many square miles. In the vicinity of Kotepad and for 
many miles both to the north and south of it the laterite is especially conspicuous forming 
numerous low bills, to the terraced alluvial valleys between which the cultivation is 
restricted. 
Raised above the main Jaipur-Bustar region are several minor plateaus; the first of these 
to be mentioned is one formed of quartzites resting on a metamorphic base and which has an 
average elevation of about 2.500 feet, like the Knrial-hiowagarh plateau. Its position is 
on the corner ot the plateau south of Deobogh. Resting on the quartzites I found, as in 
the former oase, traces of a once continuous bed of laterite. In the Poragar hills again 
we have a range which rises about 1,200 feet above the main plateau or to a total elevation 
of about 3,000 feet. The thickness of the laterite cap in this case varies with the irre¬ 
gularity of the underlying surface between from 50 to 100 feet. It would seem then that 
in this area on all elevations of 2,500 feet and upwards there are traces of laterite, which, it 
is possible, originally formed portions of a once continuous bed. This may have followed, 
however, a configuration of the country not very different from that existing at present.* 
Man}' of these laterite caps prove to be most efficient store-houses for water and are 
consequently not unfrequently the sources of perennial springs; of this the Gandamardan 
range affords numerous examples. 
Deccan Teap and Lameta Beds. 
In the scarp of the Mandla plateau representatives of the above groups have been 
observed overlying tbe Vindhyan rocks of the Chhattisgarh basin. These have not been 
subjected as yet to detailed examination, and cannot therefore be described in the present 
account. _ 
Rajmehae Seeies. 
The sandstones of the Atgarh basin and tbe fossil plants which have served to deter¬ 
mine their position as belonging to the above series have recently been described in these 
pagesf ; so far as is certainly known, there is no other deposit of rocks of the same age with¬ 
in our area ; but it may be well to record here that I noticed a strong lithological resemblance 
between certain conglomerates of the Atgarh basin and the highest beds in the Talchir field. 
The post-Barakar rocks of that area, however, have not yet been thoroughly discriminated. 
When at Khurda I was informed, on apparently reliable authority, that sandstones occur 
some folrty miles to the south-west. If such is really the case, they will not improbably prove 
to he of the same age as the Atgarh rocks. 
PMahadeva Seeies. 
Overlying the rocks of the Baralcar group, in the Talchir field, there is a considerable 
thickness of clays, sandstones, and conglomerates; these, although partially represented by 
some small outlying patches in the eastern half of the field, are only fully developed in 
the wild, thinly inhabited, and hilly region of tbe west, of which no accurate map was 
available at the time of my visit in 1875. In tbe original Talchir report these rocks were 
referred to the then recognised Mahadeva series, and were credited with an estimated thick¬ 
ness of from 1,500 to 2.000 feet; their unconformity with the underlying Barakavs was fully 
* Near Jashpur, in Chutla Nagpur, there is sueh a bed whieh entrusts hills and valleys alike, the effect being 
to round off angularities, not to fill lip vallejs to the level ol the hill tops, 
f Records, 1877, Vol. x, pt. 2, p. 63. 
