GEOLOGY. 



a foot or more of their roots exposed, appeai iug to stand on 

 stilts. It is interesting to compare the present condition of 

 mnch of Chota Nagpur with the prophecies of Mr. Hewitt, 

 formerly Commissioner of that province, in his Annual 

 Administration Report for 1883-84, who foretold the results 

 of the wholesale destruction of the forests, 



GEOLOGY. 



The land surface of Chota Nagpur is probably an 

 extremely ancient one. Omitting deposits formed by recent 

 sub-aerial denudation of the older rocks, incinding among 

 these the laterites, there is no formation younger than the 

 Gondwana system, which is believed to be contemporaneous 

 with the Upper Lias and Trias, and these Gondwana beds 

 were apparently all deposited in shallow water. The fossils 

 of the Gondwana system are chiefly eqnisetales, ferns and 

 cycadofilices, while conifers are verj rare. 1 By far the greater 

 part of the area is occupied by unfossiliferous metamorphic 

 and submet amorphic rocks covered locally by shallow, or 

 moderately deep, alluvial or sub-aerial deposits. The chief 

 exception occars in the Santal Parganahs, where enormous 

 areas are covered with basalt and other trap rocks. Most of 

 the rounded conical hills or bosses, alluded to on p. 2, 

 oonsist of porphyritic granite, * sometimes called Dome 

 Gneiss. The shelling off of the outer concentric layers of this 

 rock, causing a continual exposure of fresh surfaces, renders 

 it singularly bare of vegetation. On it species of Ficns, 

 chiefly F. tomentosa and I\ gibbosa, and more rarely the 

 Banyan, are the commonest plants. The detritus at their 

 base however will grow most species of trees, and among it 

 natural sown Tamarind is not uncommon. 



lu The plants of the Lower Gondwana include numerous Equisetales 

 while those of the upper are chiefly Cycads and conifers. The species of 

 ferns are distinct in the two divisions. "—Holland. 



2 Much of the gneiss in Chota Nagpur, exhibits no trace of foliation 

 and is lithologically granite. The Dome Gneiss is doubtfully granitic in 

 origin. 



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