38 



HAYDEN : GEOLOGY OF NORTHERN AFGHANISTAN. 



Both in Madar and in Kahmard there is a distinct unconformity 

 in the middle of this so-called Tertiary system. The beds above the 

 unconformity are red conglomerates and pebbly sandstones very sugges- 

 tive of the Gobi series, of which they may perhaps be a distant outlier. 

 They lie more or less horizontally on the folded and eroded edges 

 of the lower beds. There was evidently a considerable time interval 

 between the deposition of the two series. This unconformity escaped 

 Mr. Griesbach's attention, for he states that at Madar (which he writes 

 " Mathar ") there is a perfectly conformable sequence from the beds 

 overlying the Upper Cretaceous limestone into the red conglomerates, 

 which he regards as pliocene. The lower beds are, according to him, 

 eocene and miocene ; I had no opportunity of examining them in detail 

 and found only a few indeterminable fragments of (?) Ostrea sp. in the 

 lowest bed. Mr. Griesbach's inference of the presence of miocene beds 

 is based on fossils collected by bimself in his " Cerithium clays" ; the 

 species of his Cer/'lhium, however, was not determined and the assumed 

 miocene age of the clays is, therefore, open to question. I should be 

 inclined to doubt the existence of miocene beds in Madar and Kahmard 

 and to refer the beds below the unconformity to the eocene and, follow- 

 ing Mr. Griesbach, those above to the pliocene ; the unconformity, 

 particularly at Madar, is too pronounced for the beds below it to be 

 so closely associated in time with the overlying conglomerate. 



In Ghorband, between Siah-gird and Parsa, what was once a broad 

 river-valley, carved out of the Ghorband limestone and the slates and 

 quartzites of the Paghman range, is now filled with a thick series of 

 soft shales below, with shales, sandstones and conglomerates above. 

 Here and there a thin layer of coal, usually only an inch or two in 

 thickness, runs through the shale or sandstone for a short distance. 

 These beds lie uncont'ormably on the Ghorband limestone (Plate 8, 

 fig. 1) ; they have been considerably disturbed, and small faults are 

 innumerable; the dip is usually at a fairly high angle (30° and over] to 

 east or south-east. Between Faragard and Siah-gird, the upper beds 

 are overlain by the bright red Upper Tertiary conglomerate. 



