52 General McMahon — Note on the Hindu Khoosh. 



II. — Additional Note on the Correlation of the Eooks 



ASSOCIATED WITH THE DEVONIAN LiMESTONES OF THE HiNDU KhOOSH. 

 By Lieut. -General C. A. McMahon, F.R.S., F.G.S. 



SINCE the publication of the joint paper by Mr. W. H. Hudleston 

 and myself on " Fossils from the Hindu Khoosh," ' in which 

 the Devonian age of well-preserved fossils found in the limestone 

 member of a series in Chitral was demonstrated, my attention has 

 been called by Mr. T. H. Holland to the fact that the series in 

 Chitral agrees very closely with the rocks known to the Geological 

 Survey of India as the infra- Trias, and described, for the last time, 

 in Hazara ^ by Mr. C. S. Middlemiss, 



The Chitral series consists of three principal formations : — 

 (1) A lower bed of conglomerate with rounded to subangular 

 pebbles, varying greatly in size up to 3^ inches in diameter, lying 

 in an indurated, fine-grained matrix of slaty grit or arenaceous 

 mudstone. The pebbles consist of limestone, slates, sandstones, and 

 quartzites, with rounded, white quartz-pebbles, which recall the 

 'eggs' of the Blaini conglomerate of the Simla area. (2) A middle 

 band described by my son, who made a hurried visit to the place, as 

 red sandstone ; and (3) an upper bed of grey, dark-blue, and cream- 

 coloured fossiliferous limestone. 



In Hazara the system of rocks known to the Geological Survey 

 as the infra-Trias, on account of its position unconformably below the 

 Trias, consists in the same way of a lower conglomerate, a middle 

 sandstone series, and an upper limestone formation. These rocks, 

 originally referred to by Wynne and Waagen, were described in 

 fuller detail by Middlemiss in 1896.^ 



According to Middlemiss, the conglomerate is composed of sub- 

 angular pebbles of slates and quartzites, usually of about the size of 

 a cricket ball, but varying from mere pebbles to larger lumps, and 

 set in a fine purple sandy clay or shale. Like the Chitral con- 

 glomerate the bed — boulders and matrix — in Hazara has undergone 

 a certain amount of metamorphism. The middle member of the 

 series in Hazara is composed of purple shale and sandstone, the 

 latter predominating. The limestone in Hazara attains a thickness 

 of 2,000 feet, which, in the lowest layers, is sandy and of a deep 

 purple colour, passing up into more purely calcareous beds of 

 a lighter colour and even pink, cream-colour, or white. But the 

 limestones are generally purplish or pink in colour, thus differing 

 from the fossiliferous limestones of Chitral and resembling that of 

 the Blaini area, which also is generally pink, though occasionally 

 grey or blue. No fossils have been found in the Hazara limestone, 

 but Middlemiss suggests that they may have been destroyed by 

 metamorphism. 



1 Geol. Mag., Dec. IV, Vol. IX, pp. 3-8, 49-58, January and February, 1902. 



2 Hazara is about 130 miles S.S.E. of Chitral. The rocks in both areas have 

 a general foliation-strike of about N.E.-S.W. ; so there is no means of correlating 

 them, except by general Hthological correspondence, until the intermediate ground is 

 surveyed in detail. 



2 C. S. Middlemiss, " The Geology of Hazara and the Black Mountain " : Mem. 

 Geol. Surv. Ind., vol. xxvi, p. 17 £E. (1896). 



