4 GRIESBACH : RAMKOLA AND TATAPANI COAL-FIELDS. 



Rer river is somewhat different in general aspect. Though I believe it to 



belong to the same formation as that which forms 

 Gneiss of the Rer river. 



the Pats of the south, this gneiss never rises to any 



great height, being confined to an almost uniform level of about 1,400 feet 



and less, only here and there rising in isolated rocks a few feet above the 



denuded surface of the country — the whole, as indeed the whole of the area 



examined, being covered by tree jungle. In this stretch of gneissic 



rocks we find the picturesque falls of Rokas Kas 

 Rokas Kas Falls. 



of the Rer river. The fall is not less than about 



80 to 100 feet, and the water rushes through a series of narrow chasms 



to join in a rock-surrounded pool below, the whole forming by far the 



most striking picture in this part of the country. 



Crystalline schists. 



These form two belts, one south, one north of the coal-field, and are 

 certainly distinct from the main gneissic area. 



Descending from the great Chota Nagpur plateau in the direction of 

 Tatapani, say via, the Chanderpur road, we traverse at first an undulating 

 denuded area still belonging to, and connected with, the gneiss of the Pats. 

 Anticlinal folds in ^^^ before reaching the Gondwana basin of Tata- 

 schists, pani, we come across one or more anticlinal rolls, 

 composed of metamorphic schists, apparently faulted against the gneiss 

 and certainly faulted against the Gondwana rocks between TatapSni and 

 Khijuria-t. 



I have shown the sequence of these rock groups in fig. 1 of Plate I. 

 Standing on the slopes skirting the Gobrahill (3,220 feet) south of the 

 deserted village of Gugra, we observe gneiss of a porphyritic character 

 in situ, traversed by numerous veins of pegmatite. This gneiss forms all 

 the lower hills around the base of the Chunderpur Pats, of which the 

 plateau on the right (south) of the profile is a continuation (about 

 3,500 feet) situated near the village of Chunderpur. It is there capped 

 by sheets of trap in common with a large part of the southern gneiss 

 plateaux, here and there associated with rock-laterite. 

 ( 132 ) 



