228 



Geology of the Neilgherries. [No. 12, new series. 



the tongue, is polished by the nail, has a conchoidal fracture, 

 when treated per se ; before the blow pipe hardens into a white 

 enamel ; it does not make a paste with water, nor fall to pieces 

 when submerged in it ; occasionally it is veined with yellow and 

 blue : is not acted upon by muriatic acid : an action, though very 

 feeble, taking place under sulphuric acid, would denote that the 

 greasy feel of this mineral arises from the presence of magnesia. 

 Zeichenschiefer or black chalk I have found in a valley north of 

 Ootacamund. 



Alluvium. — Under this head I first notice the turf swamps, or 

 as they have been called peat bogs. These lie in hollows exca- 

 vated in the red soil by running streams, and in the low valleys. 



The lowest stratum of turf probably consisted of decomposed 

 ferns and grasses transported from the Hills by those streams and 

 rain. Grasses then growing on this foundation, decayed and fur- 

 nished a fresh soil for another crop, which in process of time gave 

 place to a third derived from the seeds of the preceding ; thus 

 these grasses not only gave birth to a progeny, but likewise de- 

 composing into turf contributed in the sequel to nourish it. I 

 shall have further occasion to glance at this method of vegetable 

 propagation, in speaking of the diluvium of these Hills, and I may 

 add here that the production of the ferns is a further instance of 

 it. 



Passing through a fernfield I haveobserved the living ferns rear- 

 ing their headsover the ruins of a former crop, now lying bent down 

 beneath them, and gradually passing into a vegetable soil. It is a 

 matter of considerable surprise to me that these turf swamps 

 have not been more largely turned to agricultural purposes ; the 

 deltas of some of them have certainly been drained by the natives, 

 cleared, and used as gardens. 



Rice sown would I apprehend yield an abundant return. The 

 turf of these morasses seems to be of very recent origin, stems and 

 leaves of grasses being still entire in it. Specimens containing a 

 small proportion of earthy matter will burn many hours. Under 

 a blast from a pair of bellows, or a blow pipe, a beautiful blue 

 flame is elicited, accompanied with a slight bituminous odour- 

 The depth of the turf of course varies. 



