112 



GEOLOGY OF THE LOTHIANS. 



describing these deposits, geologists have, very generally, 

 classed them under two heads, viz. Alluvium and Diluvi- 

 um, and in this order we shall very shortly examine the se- 

 veral loosely aggregated masses which are met with in the 

 Lothians. 



The alluvial rocks which occur in this district may con- 

 veniently be considered as of three kinds, viz. those result- 

 ing from vegetable decomposition, and thus forming the 

 modern analogue of coal, " peat ;"" those derived from the 



by him to Dr Win. Gregory who had them conducted under his own im- 

 mediate superintendence by two of his pupils, viz. Mr John Drysdale, 

 who analyzed Nos. 1, 2, 3, 4, and 5, and Mr J. Walker, who analyzed Nos. 

 6, 7, and 8. 



1. Basaltic rock of Largo Law, in 

 Fifeshire. 



2. Compact felspar from the Pent- 

 lands. 



Silica, . 



45.2 



Silica, 



73.5 



Alumina, 



14.4 



Alumina, with a ) 

 trace of Iron, j 





Protoxide of Iron, 



14.0 



11.23 



Lime, 



12.7 



Carbonate of Lime, 



2.5 



Magnesia, 



6.55 



Potash, 



3.55 



Soda, . 



5.22 



Soda, 



3.8 



Water, 



2.4 



Water, 



4.6 



100.47 

 Edin. New Phil. Jour. xxix. p. 388. 



99.20 

 Edin. New Phil. Jour. xxix. p. 195. 



3. Felspar rock, Wardie, near 

 Newhaven. 



4. Greenstone from Wardie, near 

 Newhaven. 



Silica, . . 37.20 



Silica, 



44.00 



Alumina, . 9.75 



Alumina, 



11.4 



Iron, . . 20.00 



Protoxide of Iron, 



22.32 



Lime, . 8.57 



Lime, . 



8.8 



Magnesia, . 3.78 

 Carbonic acid and ) 



Water, } 20 - 80 



Magnesia, 

 Water and Carbo- 1 

 nic acid, J 



2.5 

 10.5 



100.10 



99.52 



i. New Phil. Jour. xxix. p. 195. 



Edin. New Phil. Jour. xxix. p. 195. 

 5. 



