."»()<) Correspondence. 



share of attention ; we need scarcely -venture to hope — for it is scarcely 

 possible for the practised eye of this veteran officer to have overlooked 

 such an important matter, that the grouping of the mountains will form 

 the basis of his maps, and on the manner in which this department 

 lias been executed will depend the accuracy of his labours.* 



" 2nd. Unquestionable geological facts, such as the structure of igneous 

 rocks, poured out under strong pressure, the presence of fossil shells. 

 &c. lead me to the belief that several, if not all, of these vallies, • 

 (Jalalabad, &c.) were at some former time the receptacles of a series of 

 inland lakes, and the nature of the shells found (principally Planorbis 

 and Pdhidinai) seem to indicate that the water of these lakes had 

 been fresh. In this manner these grand sheets of water, separated 

 by the mountain deflexions before alluded to, wovdd appear to have 

 occupied the entire country from Cabul to the Indus, and their 

 basins may now be distinguished as the plains which afford sites 

 to the three cities of Cabul, Jalalabad, and Peshawur. The drainage 

 of the basins is most tranquilly carried on by the Cabul river, which 

 runs along the northern edges of each, conveying their united waters 

 to the Indus; but in former times, when more energetic means were 

 necessary, the mountain barriers were burst, and the shattered frag- 

 ments and rolled blocks that now strew the Kyber Pass, bear testimony 

 to its once having afforded exit to a mighty rush of waters, while 

 the Gide-gulla (Jackall's neck), or long defile east of the plain of 

 PeshawTir, clearly points out the further course of the torrent towards 

 the bed of the Indus, whence its passage to the ocean was easy and 

 natural. While at Jamrud I had an opportunity of observing a fact 

 which strongly supports the idea I have ventured to propose; for a 

 well which the Sikhs were employed in sinking within their new 

 fort, Futehgurh, and which had already proceeded to the depth of 180 

 feet, had altogether passed through rolled pebbles of slate and lime- 

 stone — the constituents of the Khyber range of hills. But the wells of 

 Peshawur, generally 20 or 30 feet deep, have passed through anything 

 but mud and clay strata. Now the fort I have mentioned is situated 

 at the very mouth of the Khyber Pass, and Peshawur is 12 or 14 miles 

 distant, towards the other extremity of the plain. If then this plain 

 were once the basin of a lake, into which a stream had poured through 

 the Khyber Pass, it is obvious that such a stream would at its very 

 entrance into the lake have deposited the rolled pebbles and heavier 

 matter with which it was charged, while the lighter mud and clay 

 woidd have floated on to a considerable distance — in other words, the 



* We have since heard from our correspondent, who states that he has seen Major Garden's 

 map, which is a highly creditable and important work. — Ed. Caj.. Joubn. Nat. Hist. 



