PAKT II.] 
59 
Blanford: Geology of Orissa. 
5. Katak (Cuttack) ok Atgaeh Geoup. 
South-west of the town of Katak is a considerable area occupied by grits, sandstones and 
conglomerates, with one or more beds of white or pinkish clay. The beds are very similar 
in general character to those last described, but there is no evidence of their connection, and 
it appears at least as probable that the Katak rocks are of later date. 
No fossils have been found in these beds except some obscure impressions apparently of 
vegetable origin in the clays. 
6. Lateeite. 
The laterite of Orissa is evidently of detrital origin, and consists essentially of small 
pisolitic nodules, chiefly composed of hydrated oxide of iron (brown haematite) and coarse 
quartz sand, cemented together, more or less perfectly, into either a firm though somewhat 
vesicular rock, or a less coherent mass, or at times remaining in a loose gravelly condition, and 
thus passing by various gradations into a sandy clay with a few pisolitic iron nodules. As 
a rule, the forms containing most iron are the most coherent, and vice versa. The more solid 
forms are largely used as building stone, having the peculiar but important property of being 
softest when first cut and of hardening greatly on exposure. 
Beneath the detrital laterite, especially when a felspathic form of the metamorphic 
rock occurs, the decomposed upper portions of the latter are frequently greatly impregnated 
with iron, and converted into a kind of lithomarge which closely resembles the detrital 
laterite in appearance, and is employed for the same purposes. 
The massive form of laterite which caps many of the higher hills in Peninsular India, 
and which is more compact than tho detrital laterite, is not known to occur in Orissa. 
7. Alluvium. 
a. Older Alluvium of the Coast Plain. 
In the neighbourhood of the hills and frequently for many miles from their base, the 
alluvium of the plains consists of clay and sand, usually more or less commingled, and, in 
most places, containing calcareous concretions (kankar or gutin) and pisolitic ferruginous 
nodules. This deposit passes, as already mentioned, by insensible degrees into laterite on the 
one hand, and into tho more recent delta alluvium on the other, but in its typical form, it is 
well distinguished from both by being more sandy and by containing nodular carbonate of 
lime or kankar. 
Tho age of this alluvial deposit is shown by its surface having been modified and 
rendered uneven by the action of rain and streams; so that the country composed of it is 
more or less undulating. 
Whether this formation, or any portion of it, is of marine origin is a question hitherto 
undetermined. So far as it has boon yet examined, it appears in Orissa to be unfossiliferous. 
The greater portion has, doubtless, been produced by deposits washed down by streams and 
rivers from the higher country to tho westward, and it appears probable that a portion of 
these have been, deposited along tho coast. But other deposits have been, in all probability, 
formed upon tho original marine beds by the additional accumulations brought down by 
streams and washed by rain from the hills, so that it is questionable whether tho lower 
marine beds, which probably exist, are anywhere exposed. 
