56 Records of the Geological Survey of India. [vol. v. 
Sketch oe the Geology oe Oeissa, ly W. T. Blanfoed, A. R. S. M., F. G. S., Deputy 
Superintendent, Geological 'Survey of India. 
The province of Orissa consists, geologically as well as geographically, of two very distinct 
portions,—the one, a belt of nearly flat country from 15 to 40 miles in breadth, extending along the 
coast, and the other, an undulating area broken by ranges of hills in tho interior. The former 
is entirely composed of alluvial formations, the greater portion of its surface being probably 
composed of deposits from tho great river Mahanaddi and the smaller streams, the Bramini 
and Baitarni. Near its western limit alone, a few hills of gneissose rock rise from the 
alluvial plain, especially between the Bramini and Mahanaddi. The inland area, on the other 
hand, is chiefly composed of rocks of very ancient date, so completely altered and crystallized 
by metamorphic action, that all traces of their original structure are lost, and any 
organic remains which they may originally have contained obliterated. The same rocks 
cover an enormous area in Eastern and Southern India, and are usually spoken of in works 
on Indian Geology, as the Crystalline or Metamorphic series. 
Further exploration in the little known Tributary Mehals will, doubtless, show tho existence 
of beds belonging to other formations, but hitherto tho only instance in which any considerable 
area is known to be occupied by rocks of later date than the metamorphics, is in the tract known as 
the Talchir Coal Field in the estates of Talckir, Ongdl, Bamda, Atmallik, Radakol and Denkanal. 
High up the Bramini, a series of very slightly altered or unaltered rocks, comprising slates 
with jasper, quartzite and schistose beds, are known to occur ; but it has not been ascertained 
whether they extend into the district administered from Ivatak, though they are believed to 
occupy portions of Keunjur and Bonai. 
The greater portion of the Tributary Mehals has never been explored geologically, and 
tho information procurable as to their character is most imperfect. It is possible that other 
coalfields may exist, though not probable. Even the Talchir Coal Field has only received, for 
the most part, a very hurried examination. 
Excluding the formations of which no accurate information has been obtained, such as 
the slates, quartzites and jasper, believed to occur in Keunjur and Bonai, the following is a 
list, in descending order, of the rock systems hitherto described as occurring in Orissa. 
8. Blown sand. 
7. Alluvium. 
b. —River Delta deposits. 
a .—Older alluvium of coast plain. 
6. Laterite. 
5. Katdh or Atgarh sandstones. 
4. Mahadeva ? or Panehet sandstones and grits. 
3. Damuda sandstones, shales, and coal, 
2. Talchir sandstones, shales, silt, and boulder bed. 
1. Metamorphic or crystalline rocks. 
A brief description of the character of each of these formations, as found in Orissa, is 
appended. 
