568 Correspondence. 



a horizontal position at the line of junction, then he was entitled 

 to infer that the "igneous rocks" were erupted anterior to the deposi- 

 tion of the lacustrine formation ; for if it had taken place after the de- 

 position, then both the position of the strata and the structure of the 

 rock at the line of junction, would have been altered. To pay attention 

 to these two circumstances is of the utmost importance, in order to 

 ascertain the relative ages of the Neptunian and Plutonian or volcanic 

 rocks, and we would therefore direct particularly the attention of Dr. 

 Lord and Capt. H. Drummond, the latter of whom is now engaged in 

 making a geological survey of Cabul and Affghanistan, to these points. 



< h 



{ 



a Igneous rocks. 



yy I ■ A 



^ ~ -\ b Lacustrine deposits. 



< 



3rd. " Connected with these three basins, and joining that of Cabul al- 

 most at a right angle from the north, is the plain of Koh-i-daman (the 

 mountain's skirt) which stretches away to the very foot of Hindu Kush, 

 and gives exit at its northern end to four several routes,* by which 

 that chain may be passed. It is an extensive and fertile plain, bounded 

 on all sides by primitive hills, those to the north-east and south being 

 chiefly of slate, including all the gradations from clay to mica, and 

 even at times closely bordering upon gneiss, while the ridge to the 

 west shews at the base granite, and it is at the base and along the 

 windings of this, that occur the vineyards, orchards, and gardens of 

 Shuterdarra, Istalif, and Isterkhech, so famed in the commentaries of 

 the Emperor Baba." 



On the first day's march towards the plain above mentioned, he says — 

 " The trees had already put on their autumnal tint. The mountains ex- 

 hibited the grandest varieties of light and shade. Clouds still lingered 

 amongst their inequalities, and rested here on a spiral cliff, there on a 

 lengthened streak of snow, which deep in a ravine had resisted the whole 

 force of the summer's sun. The dead nettle, the thistle, the dog-rose 

 covered with hips, the may-flower, glistening strawberries, the wild mint, 



* From a point towards the centre of the plain (Dush-i-Bagram) I found the bearings of these 

 four passes as under — 



Punjthan, N. 



Ghutuh N.W. 



Punvon, .... 2 N.W. 



Goorbund 50 N.W. 



