36 ' TALCHEER COAL FIELD. 



In proceeding to a more detailed description of the rocks of the 

 district, the following order will be adopted : — ■ 

 1st. Igneous rocks. 

 th^l/lrSc.!' 2.^d Metamorphic ditto. 



3rd. Sedimentary deposits. 

 4<th. Rocks of chemico-aqueous origin. 

 The igneous rocks of the district are limited in extent and importance, 

 occurring only as small dykes and veins traversing 



iGNEOnS ROCKS. ■ m^ • ■ 11 ^ p 



the gneiss, ihese are principally composed oi 

 granite, but occasionally of a rock of dioritic character. The granite 

 veins vary much in composition, some being nearly pure quartz and 

 felspar, others again containing felspar of two different kinds (one 

 being orthocla?e felspar of the adularia variety, the other perhaps albite), 

 also large crystals of mica and quartz. The dykes are very narrow 

 none exceeding 2 feet in breadth, and the majority being probably 

 under 4 inches ; those of smaller size are very numerous. It appears 

 strange, considering the general distribution of these granite veins, 

 and then- great number in some localities, that no nucleus, however 

 small, of igneous rock has been discovered in the district, although 

 doubtless, judging from the highly granitoid condition of the metamor- 

 phic rocks in many places, some such nucleus does exist at no very great 

 depth. 

 The minerals of the granite within the area described are not numer- 

 -.. , . ,, ous. The intruded rock of most frequent occur- 



Miuerals lu the gi-a- ^ 



"''"^' ^°' rence is a highly felspathic, largely crystallized 



variety of granite, sometimes containing crystals of black tourmaline of 

 large size. This occurs in veins from 1 to 2 feet in thickness ; it is seen 

 in the bed of the River Brahmini, near Kamlong, in a nullah near 

 the village of Gutiapal and near the village of Ramidi Near the 

 last-mentioned place a dyke-formed vein of about 18 inches in breadth, 

 which can be traced for some distance rising above the general 



