LOWER TRANSITION ROCKS. I2J 



4. Haematite. 



3. Trappoid. 



2. Trap. 



1. Schists in great thickness (grey, etc.). 



The Tonashagiri haematites die out, I believe, before trending round 

 the south-western corner of the hills. They underlie the manganifer- 

 ous argillites and the limestone and quartzite mentioned above (page 

 1 23). The general dip of all the formations around this corner is from 

 40 to 45 north-east or northward. 



The position occupied by these beds relatively to the whole 

 Sandur series resembles the position which (as will be seen further 

 on) are occupied by four other sets of formations which all underlie 

 or appear to[underlie the great Joga trapflow, which plays so important 

 a part in the area lying between the Sandur and the copper mountains 

 synclinals. The four sets in question are the " outside " group of 

 haematites east of the Appian end of the synclinal (p. 116), the Joga 

 hills series (p. 126), the Lingadahalli series (p. 127), and the Mallam 

 Konda beds (p. 130), all of which seem to be to some extent uncon- 

 formably overlapped by the Joga trapflow and the yet younger great 

 haematite series. 



To the west of Somulapur, opposite the western mouth of the great 

 Schists near Somula- Ubalagandi gorge, the Dharwars consist of 

 P ur# hornblendic, micaceous and chloritic schists 



which were deposited on a very hummocky granite gneiss surface, 

 giving rise to a very rugged fringe of boundary impossible to be 

 shown in detail even in maps on the largest possible scale. Many of 

 the large hummocks of the granite gneiss have their tops exposed, 

 while their bases remain covered by the schists which lap round them. 



Talcose schists are also to be seen here and there to the west of 

 Somulapur, but in much lesser quantity than at the other localities 

 enumerated above. Only the Atlas sheet No. 58 was available at the 

 time I mapped this tract, and on such a minute scale it was not pos- 

 sible to show the many changes of schist met with. 



To the south of Somulapur the boundary of the Dharwars became 

 increasingly ragged, and a long narrow strip of green hornblendic 

 schist juts out like a peninsula for more than a mile and stretches 



( 127 ) 



