226 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 6, 



about twenty-two miles E. of the Malsej. A few miles beyond this 

 point the southernmost range becomes almost impracticable, expand- 

 ing into broken table-land, and barring all further progress to the 

 east, by pushing out towards the south the branch which forms the 

 watershed between the Beema and the Seena. 



The trap formation in this district consists of an alternation of hard 

 and soft beds of great thickness, and remarkable for their uniform hori- 

 zontality. The hill ranges, which include in their height several such 

 alternations, present a peculiar streaked appearance, the hard beds 

 usually having bare mural escarpments blackened by the weather, 

 while the softer beds, decomposing at an angle of about 45°, are 

 covered by rich vegetation. The strata are undisturbed and almost 

 horizontal ; the surface of the country is generally conformable to 

 them, and remarkably free from considerable undulations. 



As the mechanical structure of all trap rocks depends principally 

 on the particular circumstances under which they have cooled, it is 

 not surprising that such structure should vary exceedingly in short 

 distances even in the same stratum, although the predominant cha- 

 racter of the bed does not disappear. 



The line between Koobee and the Gungathuree will always rest 

 either on a stratum of amygdaloidal rock, or on the bed of gravel lying 

 immediately beneath it. 



The latter stratum is from 50 to 90 feet in thickness, and is (for 

 a member of the trap formation) remarkably uniform in character : 

 it is of a whitish grey-colour, and in structure something between 

 gravel and marl ; it frequently contains thin beds of friable, spongy- 

 looking amygdaloid, and everywhere abounds in nodules of chunam. 

 It is well developed along the Kristnawuttee, between Murr and Din- 

 gora, and also between Peepulgaom and Ootoor ; to the north of 

 Alleh it forms the bed of the Mool, and the mountain torrents de- 

 scending to that river from the Bramanwaree hills, have hollowed out 

 deep chasms in it, whenever they descend to its level. 



The amygdaloid which rests on this bed, varies exceedingly in 

 colour, structure and hardness ; in some places it is as soft and fria- 

 ble as marl, in others as hard as columnar basalt. It is sometimes 

 thin-bedded and fissured in all directions, and at others rises in per- 

 pendicular and solid escarpments to the height of 200 feet. 



Of these varieties the friable marly beds are the rarest ; the hard- 

 est sorts appear to be generally either of very limited thickness or 

 much fissured in all directions. The beds of moderate thickness fre- 

 quently resemble lias in appearance, but are generally softer and 

 coarser-grained. The highest and most compact-looking escarpments 

 are often as soft as freestone. 



On this bed of amygdaloid rests the nodular basalt (basalt en 

 boules) ; the nodules that compose it vary from one pound to several 

 tons in weight ; they are very hard, generally spherical, and enve- 

 loped in thin, grey, friable concentric coats like those of an onion ; 

 they are imbedded in a matrix resembling the soft bed already de- 

 scribed. The nodules may therefore be easily separated by a crow- 

 bar and rolled away. 



