548 



On Chalk Marl. 



Insoluble in acids, 42*81 : — Percent. 



Lime 1*61 



Magnesia ;. •91 



Potash 2-16 



Scda -42 



Alumina with a little oxide of iron . . . 7 '88 

 Sihcic acid and sand . . . . .29*83 



100 00 



No. 3. The Upper Gault is of a dirty yellowish colour, not 

 quite so stiff and tenacious as the lower members. The agricul- 

 tural characteristics, after drainage, are very similar to those of 

 the middle gault. We have never seen it employed as an altera- 

 tive manure ; neither would we recommend it, on account of its 

 comparative deficiency in lime — at any rate, wherever the middle 

 gault could be procured. 



Analysis of the Upper Gault (No. 3). 



Combined water with a little organic matter 

 Soluble in dilute acids, 31*85 : — 

 Silicic acid (siliea) 

 Carbonic acid 

 Sulphuric acid 

 Phosphoric acid 

 Chlorine 

 Lime , 

 Magnesia 

 Potash . 

 Soda . 



Protoxide and peroxide of iron 

 Alumina .... 

 Insoluble in acids, 62*68 : — 



Lime . . . . 



Magnesia .... 



Potash 



Soda ..... 

 Alumina with a little oxide of iron 

 Silicic acid and sand 



Per Cent. 



5*47 



24-80 



none. 



trace. 



ditto. 

 •03 

 •75 

 •26 

 •35 

 •16 



4-56 

 •94 



1*29 

 •82 

 1-57 

 •64 

 11*29 

 47*07 



100*00 



The above divisions of the gault are arbitrarily made, but we 

 have employed them as they are readily recognizable, though 

 each one gradually shades off into the other. The middle divi- 

 sion is naturally the most productive. 



No. 4. Soft rock above the Gault. — Immediately above the gault, 

 with the upper member of which it insensibly intermingles, lies 

 this soft white-brown rock^ having the appearance of a rich lime- 

 stone. It is very remarkable on account of its low specific gravity, 

 and still more so. considering its position, by reason of the very 

 small quantity of carbonate of lime which it contains. There are 



