520 



HENRY F. BLAKFOKD ON THE 



The plant-bearing formations of India exhibit some diversity of 

 character in different parts of the area ; so that it will be convenient 

 to notice them nnder their several geographical divisions, viz. : — 

 I. "Western Bengal; II. Orissa, Sirguja, South Behar, and South 

 Eewah ; III. the Satpura basin of Central India ; IV. the Godavery 

 basin; Y. Trichinopolv and Madras; and YI. Cutch (see Map, 

 PL XX V.). 



I. The first division includes the coal-basins of the Damuda valley 

 (all of which have been described and mapped in detail) the Eajmahal 

 hills, and the numerous small basins, some less than a square 

 mile in extent, which are dotted over the gneiss plateau to the west 

 of the Gangetic delta. Of these basins (with the exception of the 

 Eajmahal hills) the Eaniganj coal-field may be taken as the type. 

 In it all the lower groups of the plant-bearing series of Bengal are 

 characteristically developed and attain their greatest aggregate thick- 

 ness. Of these Mr. W. T. Blanford has distinguished the following, 

 enumerated in descending" order*: — 



1 . Coarse sandstones and conglomerates 500 feet. 



2. The Panchet group 1500 „ 



3. The Eaniganj group 1 |" 5000 , , 



4. The Ironstone shales v Damuda series ...-< 1400 „ 



5. The Barakar group ] [2000 „ 



6. The Talchir group 800 „ 



making a total of 11,200 feet. In the Jherria field to the westf, 

 the Barakar group has a thickness of 3000 feet ; and in the Bokaro 

 field, still further west J, the topmost sandstone formation is 1500 

 feet, the Panchet group 1800 feet, and the iron shales 1500 feet ; 

 so that the total maximum thickness of all these deposits, as repre- 

 sented in the Damuda valley, is not less than 12,600 feet. 



Plant-remains have been met with occasionally in all the sub- 

 divisions ; but in many cases they are fragmentary and ill preserved. 

 The fossil flora of the Eaniganj group is the best preserved, and, 

 although never yet described and published in a complete form, is 

 the best-known. Dr. Oldham gives the following numerical list of 

 the species of the Damuda series §, including the recognizable plants 

 of the Barakar group. I exclude one species of Zamia, given with 

 a [?] in the list, since no plant of this genus has ever been met 

 with by the Survey in these rocks, and its authenticity is very 

 doubtful || . 



Sphenophylluni 3 species. Pecopteris 4 species. 



Vertebraria 2 ,, Glossopteris 5 ,, (?) 



Phyllotheca 2 „ Calamites 1 „ 



Cyclopteris 1 „ Schizoneura 2 „ 



The fossils of the Barakar group differ from those of the Eaniganj 



* Mem. G. S. I. vol. iii. part 1, p. 31. Group 1 is designated as the Upper 

 Panchet ; but this name has since been abandoned. And for the name Lower 

 Damudas (Group 5), the name given in the text has been universally substituted. 



t Hughes, Mem. G. S. I. vol. v. Art. 4, p. 245. 



| Hughes, Mem. G. S. I. vol. vi. Art. 3, pp. 3, 67, 59. 



§ Mem. G. S. I. vol. ii. p. 326. || See note to the list, op. et he. cit. 



