50 mallet: geology of darjiling and western duars. 



Then a blank, beyond which the ordinary sandstones, &c, come in. 

 These beds remind us of the mottled red clays, &c, which Mr. Medlicott 

 describes at the base of the Nahan group. 



Conglomerate beds are more largely developed in the Baxa Tertiaries 

 than in those of Darjiling ; as usual, they occur near the top of the group. 

 In the ravine below and immediately west of the right picket at Baxa 

 there is a considerable thickness of them — rolled pebbles of sizes up to 

 6 inches diameter in an arenaceous matrix. Similar bands are found in 

 the Rhekua naddi, which flows into the Sankos. 



A comparison of the above lithological characters with those given 

 m L . . by Mr. Medlicott for his Nahan group of the 



Tertiaries represent J or 



Nahan group. north-western Himalayas * shows the strong simi- 



larity between that group and these Darjiling beds. The Nahans are 

 essentially the ' lignite-sandstones ' of the North- West; and our rocks 

 further agree in the occurrence of ferruginous beds and of red clays 

 and sandstones near the base, as well as of conglomeratic bands near 

 the top. Mr. Medlicott felt satisfied from his examination of the 

 Tertiaries further east, in Upper Assam, that they there represent the 

 Nahan group ; and he further pronounces my specimens from the 

 Darjiling country to be of a decidedly Nahan type. 



* Vol. Ill, pt. 2, p. 114. 



( 50 ) 



