20, On the Occurrence of Limburgite in British 



Baluchistan. 



i 



By Hem Chandra Das-Gupta. M.A., F.G.S. 



t/ 



In the year 1 907 I had an opportunity of visiting parts of 

 British Baluchistan in charge of a party of students from the 

 Presidency College, Calcutta, The palaeontological collections 



1 and in 



the present note I propose to give an account of the trap rock 



-Li-i. 1 • ,1 • 11 1 1 -f TT„™, J„~ /lr> + 3ll°9«'lVr 



Hamandun 



long. 67°24'E.). 



The first mention of the occurrence of Deccau trap in Balu- 

 chistan was made by Mr. Oldham who has described the occur- 

 rence of " ash beds and even basaltic trap apparently interbedded 

 with the uppermost beds of the Dunghan group in the Bolan 

 Pass." 4 A geological map of the area has been published by 

 Mr. Vredenburg* and it appears that the following sequence has 

 been recognized : — 



Intrusive gabbros and serpentines, frequently . 



chrome-bearing. f 



Dunghan .roup. > Senonian. 



Bedded agglomerates and basalts of Haman- ) 

 dun (Deccan trap). 



The rock to be described in this short note was obtained 

 from the lowest member of the Senonian group just referred to 



From the considerations given below it will appear a 

 the rock under description belongs to the class of >»'<0 m «*" S( " 



(BoKcky), i.e., it is an mtra-basic lava flow and a bed to the 

 limburgites of Rosenbnsch. Limburgite is a rock of rafcer 

 rare occurrence in India. For the first mention of th» roc* 

 within India we are indebted to Sir Thomas Holland L Jfcvw 



denburg has described limburgite from the Baluchistan desert 

 »hile Mr. Adye lias also noticed the same rock in ^ £g£ 

 trap of Kathikwar.' As far as my information goe*, tte K*g» 



war finds are the only recorded **%*££ *££ "££5 

 °f the Deccan trap. They have not, however, 



1 Journ. As. Soc. Bengal, Vol. VII, pp. l " 3 (19H) ' 



2 Geology of India (2nd edition), p. 29 - 



s Rec. Geol. Surv. Ind., Vol. XXXI, pi. l *l l ?'>- Mi ddlemiss occurs 



* This rock to which attention was drawn b>ur. - ^^ 



^ar Palakod (Salem) and is an enstalite-hmburgite. ( 

 J nd., Vol. XXX, p. 19, footnote). _ 



6 Mem. Geol. Surv. Ind.. Vol. XX XI , P- ^ 94 _ 95> 97 . 



8 Economic Geology of Navanagar State, pp. »» 



