126 Notices of Memoirs — The Geological Survey of India. 



into two halves by a shallow furrow. Thus, each moiety of the 

 costa is provided with its row of scales. The adjoining rows of the 

 same costa meet in an obtuse angle, the point directed downwards. 

 This position of the scales on the theca or epitheca of the coral gives 

 them an exothecal character, and reminds one of the corresponding 

 position of the many opercular valves left on the epitheca of Cysti- 

 phyllum prismaticum, as well as sometimes on that of Goniopliyllum 

 pyramtdale (See Geol. Mag. 1866, PL XIY., Fig. 4 o, and Ofvers. 

 Vet. Ak. Forh., 1868, pi. vi. fig. 4). I am therefore inclined to think 

 that the opercula of the Eugose Corals, although much diversified, 

 are secretions of an exothecal nature, homologous to the small scales 

 of PhoUdopJiyllum Loveni, and perhaps also to the scales and oper- 

 cular valves of the Primnoae. . 



n. — The Geological Survey of India. 



Memoirs of the Geological Survey of India. Vol. VII., Part 2. 1870. 

 Records of the Geological Survey of India. Vol. III., Part 4. 1870. 



THIS Part of the Memoirs contains two reports by Mr. T. W. H. 

 Hughes, F.G.S., etc. 



1. On tJie KurJiurhari Coal-field. — This coal-field, situated in the 

 district of Hazaribagh, although one of the smallest in the Indian 

 empire, has for many years attracted public attention, owing partly 

 to the superiority of its coals to those from any of the fields in the 

 Damuda valley, and partly to its position as a source whence to 

 supply the wants of the East Indian Eailway and the larger towns 

 west of Dinapore. It occupies an area of about eleven square miles, 

 in which occur the Talchir and Damuda series, and also two inliers 

 of crystalline or metamorphic rocks. The area is bounded by 

 crystalline rocks. The distribution of these rocks is shown on a 

 small geological map, drawn to the scale of one inch to the mile. 



The Talchir series occupies but a small portion of the field ; it 

 consists of conglomerates, shales, and sandstones, without coal. 



Of the Damuda series, only the lowest or Barakar group is repre- 

 sented. This group comprises pebbly-beds, grits, and sandstones, 

 with beds of carbonaceous shale and seams of coal. The structure 

 of the coal-field is, roughly, that of a basin. Trap-dykes occur in 

 great frequency, and, of course, will have impaired the coal through 

 which they pass. 



There are not more than three, or at most four, workable beds of 

 coal, and it is chiefly with a full description of these, at the different 

 localities where they crop out, or have been already worked, that 

 this Memoir is occupied. 



The principal seams exhibit an irregularity which is characteristic 

 of the Barakar group. Mr. Hughes estimates eighty millions of tons 

 as being the probable amount of coal available in this field. 



2. On the Deoghur Goal-fields. — The name Deoghur is applied 

 generally to three outliers of coal-measures which occur in the 

 neighbourhood of the Adjai Eiver, to the east of the Kurhurbari 



