C. PALEOZOIC. 



nth. Permian group or New Red Sandstone. Thick beds of sandstones 

 3,000 feet and shales of fluvitile origin. Belong to the Gondwana 

 system. The Lower Series are the Talchir and Damuda 

 rocks which correspond with the Permian rocks of 

 Europe. 

 I2th. Carboniferous system. Ranigunge, Barrakar and Jheria fields. Be- 



15,000 feet. long to the Gondwana system. * 

 ijih. Old Red Sandstone. Scarcely represented in India. 



go, ooo feet. 



I4th. Lower Silurian. Shales, limestones, sandstones and conglo- 

 3o'aoo feet. merates. Scarcely represented in India. Found on the 

 top of Himalayan Gneiss. 



D. Azoic. 



15th. to i8th Archcean rocks. Oldest known rocks of India are Gneiss 

 26,000 feet, underlying the ancient Palaeozoic rocks. They belong to 

 two periods. The Older or Bundelkhand Gneiss (i8th) is 

 covered unconformably by certain transition or Sub-me- 

 tamorphic rocks ( called also Vindhyan system of rocks ) 

 which (i5th) as they approach the Younger Gneiss become 

 altered (i6th) and intersected by Granite intrusions. The 

 Younger or Peninsular Gneiss (i7th) is also unconform- 

 able to the Older Gneiss. In West-Himalaya,s both the 

 Gneisses occur. The Upper Himalayan Gneiss (i6th) is 

 formed by the metamorphism of Older Palaeozoic rocks. 

 The Lower Himalayan Gneiss is truly Archaean. 



* Gondwana system : The upper strata of the Palaeozoic and the lower strata 

 of the Mesozoic groups in India(z'.. from Jurassic down to Carboniferous rocks) 

 are included under the Gondwana system. They have been probably deposited 

 by rivers and are chiefly composed of sandstones and shales. Plant remains are 

 common but not animal remains. Rajmehal hills, Damoda Valley, the Tributary 

 Mehals of Orissa and Chhatishgarh, Chutia Nagpur and Upper Son Valley, 

 the Satpura range at the Godavery basin, are the localities representing the 

 Gondwana system. 



D 



