Geological Society of London. 281 



noticed ; those beneath the Carboniferous Limestone west of the 

 Indus, those near Ainb and Sakesir peak, associated with the " purple 

 sandstone," " Obolus-beds," and " speckled sandstone," and those in 

 the eastern portion of the Salt Range, amongst the beds of the 

 " Salt pseudomorph zone " and " Olive group," being successively 

 passed in review, and their relations to overlying and underlying 

 strata explained. It was shown that boulder-beds and conglomerates 

 containing pebbles and boulders of the same crystalline rocks are not 

 confined to one horizon. 



In conclusion, the resemblance of the rock, of which the pebbles 

 containing Conularice, etc., were formed, to that forming some of the 

 " magnesian sandstone " and " O&oZws-beds," was pointed out, and it 

 was suggested that the pebbles in question may have been derived from 

 representatives of those beds formerly existing to the southward. 



2. " On the Phosphatic Beds in the Neighbourhood of Mons." By 

 M. F. L. Cornet, For. Corr. G. S. 



The beds are situate in the province of Hainaut, near the town 

 of Mons (Belgium) ; the workings have increased of late years, and 

 in 1884 yielded 85,000 tons of phosphate. 



They occur in the Upper Cretaceous, which is exceptionally well 

 developed in the district, filling a trough in the Carboniferous rocks, 

 and itself denuded for the reception of Tertiary and Quaternary beds. 



Omitting all Cretaceous groups below the middle of the fifth stage, 

 the following is the sequence of the Cretaceous beds which contain 

 the phosphatic series : — 



C. Tufaceous Chalk of Ciply, with the Poudingue de la Malogne at 



its base. 



D. Brown Phosphatic Chalk of Ciply. 



E. Coarse chalk of Spiennes. 



F. White chalk of Nouvelles. 



F is a pure white chalk with some flints and contains Belemnitella 

 mucronata, Bhynchonella octoplicata, Terebrutula carnea, Anancliytes 

 ovatus, etc. — an horizon well known throughout North-western 

 Europe. Series E and D represent one geological horizon, charac- 

 terized by Ostrcece, Brachiopoda, etc., in great numbers, but also 

 containing Belemnitella mucronata, and lying between two distinct 

 planes of erosion. 



The Brown Phosphatic Chalk (D), which forms the Upper division 

 of the series, is about 70 feet thick, and may be described as con- 

 sisting of three parts ; the upper is tolerably pure carbonate of lime, 

 but in its lower portion becomes charged with brown granules mainly 

 consisting of phosphate of lime ; these continue to increase towards 

 the central or main phosphatic mass, which is also highly fossili- 

 ferous in places. This central portion constitutes the main phos- 

 phatic beds, but the amount of phosphoric acid (dry) is not more 

 than 12 per cent. 



Hence, it is necessary to increase the richness in phosphate of 

 the deposit in order that it may be available for conversion into a 

 superphosphate. This may be done by mechanical means. 



But nature has already partially anticipated this process, and the 



