THE TRANSITION SERIES. 37 



some small outcrops in the low country are of undecided age, but they 



may be of the Cheyair and Nullamallay groups. 



No fossils have as yet been discovered in these rocks, or in their 



representatives in other parts of India, so that the 

 Age of series. . . , . 



little that is definitely known of their possible age 



is only ascertainable from their stratigraphical relations. In this field itself 

 they are not directly associated with any other formations, but in the 

 Cuddapah district they are unconformably overlaid by the Kurnool series, 

 which is again unfossiliferous. In the adjacent Madras district they 

 are, I think, directly overlaid by the upper Grondwana beds ; and in this 

 area, these beds, or the plant shales, contain pebbles of the Cuddapah 

 rocks. In the Godavari district, the representatives of the Kurnool and 

 Cuddapah series are each overlaid by the oldest f ossiliferons rocks of Pen- 

 insular India, namely, the Talchirs, which are supposed to be of upper 

 palaeozoic age ; hence the Cuddapah series must be very low palseozoic 

 rocks, if not much older. In our Indian classification, the Cuddapahs, 

 GwAliors of Central India, and the Kaladgis of the interior Deccan, are 

 provisionally ranged together as upper transition rocks. 



In this region the rocks of the series are either quartzites or clay- 

 slates, the former being the more prevalent, and 



Distribution. , . . 



giving the grand cliffs and scarps so characteristic 



of the above hill ranges. Kambak Droog may be said to consist almost 

 entirely of quartzites, though in its southern portion its base is of gneiss, 

 capped, however, by a good thickness of quartzite sandstones and con- 

 glomerates. The Kalahasti range, though mainly of thick beds of quartz- 

 ites, still shows many bands of coarse clay-slates. The Veligondas, up 

 to Venkatagiri, consist of some very decided and thick beds of clay- 

 slates among still preponderating quartzites, the range of hills being 

 thus broken up into many long valleys and some conspicuous ridges and 

 outstanding cliffy masses, such as Venkatagiri Droog and Koyamon 

 Konda. The strike of these beds runs north-north-west, and, as the range 

 of hills bends more northerly, these with their eastward dip gradually 

 become hidden under, or are succeeded by, the further higher groups of 



( 1*5 ) 



