MIDNAPOKE, OKISSA, &C. 271 



meratic variety, every gradation may be traced into a homogeneous 



pisolitic mass composed of small nearly spherical nodules of sandy 



ferruginous matter generally speaking arrano-ed 



Nodivlai- or pisolitic. . . *= J f = a 



in concentric layers, with a black or nearly black 

 , central spot, or nucleus. This is occasionally composed of magnetic- 

 iron, but is often decomposed and is then in the state of a yellowish 

 ochre, or has disappeared and left a small cavity. 



One of the most remarkable features about this curious rock is the 

 Uniformity in size of extraordinary regularity or uniformity in ' the size 

 "°'*'^^^' of these small nodular concretions, or rounded 



masses. Few of them are so much as one inch in diameter ; the pre- 

 vailing size being from one half to three quarters of an inch, but over 

 many square miles of such a deposit it would be almost impossible to 

 discover a single nodule double this average size. 



Frequently this detrital or nodular laterite is like a loose gravel, each 

 nodule being separate and free, but not uncommonly it has been cement- 

 ed into a solid mass, which can be quarried like any other rock. Many 

 places may be seen in pits along the road side, where this gravelly later- 

 ite is extracted as road-metal for which it is admirably adapted ; and in 

 these pits the connection of the more solid variety, with the more loosely 

 coherent, may be traced. In all cases it seems to have resulted from 

 a reconsolidation or subsequent cohesion of the previously free particles 

 or nodules : and this seems to have been produced by the infiltra- 

 tion of water, which decomposing and partially taking up the iron 

 has again re-deposited it, forming a cement between the nodules. This 

 receraenting is always seen along lines of jointing or cracks, by 

 which such water has trickled through the rocks, and the solid 

 portions are seen irregularly disposed along the irregular directions of 

 such infiltration. 



These re- cemented masses of the nodular laterite (kunkur, or iron 

 kunkur of the natives) formed from the already dried-up and exposed 



