Chap. 13.] w. blanford^, avestern india. 65 



tertiaries of Surat and Broach into groups^ and to represent the whole 



by but one colour on the map. {a) 



Of the thickness attained by the tertiaries of Surat and Broach it 



^^. , ^ , , is difficult to form an estimate for the same reason. 



Thickness of beds. 



No continuous sections exist,, and it is difficult to 

 say how large a portion of the apparent thickness is due to repetitions 

 caused by anticlinal and synclinal rolls in the beds or to faults. In 

 the stream which runs past Euttunpoor^ the rocks are seen for above 

 5 miles. The dip varies much^ but the average can scarcely be less tlian 

 10°. This would give a thickness of 4^600 feet^ which appears excessive, 

 and is^ after all, a mere guess. At Turkesur the lower group is about 

 2 miles wide, and dips at angles of from 5° downwards. Taking the 

 average dip at 5° the thickness would be about 900 feet, but supposing 

 that it is lower, which is more probable, and reckoning it at 3° the total 

 thickness would be 560 feet. 



Chapter 13. — Ossieerous gravels and other old alluvlil deposits. 



In treating of the general physical geography of the Nerbudda and 



Taptee valleys, the presence of great plains of alluvium was especially 



noticed. One such plain, that occupying the Nerbudda valley from 



Jubbulpore to Hoshungabad, has already been described in these memoirs 



(a). It has been already suggested that all the fossils of the Sind.nummulitics are 

 not of one age. In the Quarterly Journal of the Geological Society for 1864, Vol. XX, 

 p. 65, several reasons are given by Mr. H. M, Jenkins for believing that some of the Sind 

 beds massed as eocene by most previous observers were of, at least, miocene age. He 

 showed that some rocks of Java believed to be miocene contained a Vicarya very near the 

 F". Verneuilli of Sind, and that F". Verneuilli was associated in Sind with shells occurring in 

 the miocene of Europe. At the same time Dr. Martin Duncan, in a separate note, showed 

 that a large number of corals from Sind, not described by M. M. D'Archiac and Haime, 

 have miocene and even pliocene affinities. The examination of Surat and Broach and of 

 the tertiary beds there occurring was made early in 1863 (January and February), a year 

 before Mr. Jenkins's paper appeared, and in a brief visit to Sind in November. 1863, I saw- 

 strong reasons for suspecting that a division of the nummulitic formation there should be 

 made. Indeed the occurrence of forms of more recent appearance than nummulitic in the 

 Sind rocks has been for some years kno^vn in India. 



I ( 337 ) 



