By the Rev. John Adams. 



281 



an acre is paid for it to the landowner, and upwards of 10,000 

 bushels are annually sold. Generally layers of clay and marl 

 alternate with the peat, as in the following section of a cutting 

 S. W. of Thatcham Station. 



Fig. 4.— Section in the Alluvium of the Kennet, S.W. of Thatcham Station. 



o. Shell-marl 



h. Peat 



e. Peaty clay 



d. Shell-marl 



e. Peat 



/. Brown clay with broken shells 

 g. Shell-marl, 



1 ft. 6 in. to - 



2 6 

 8 



But sometimes we find vertical masses of peat in the midst of 

 shell-marl as shown in the following, sketch of alluvium at Hoe 

 Benham Marsh 4 miles west of Newbury. 



Fig. 5. — Sections in the Alluvium of the Kennet west of Newhuiy. 

 o. SoiU h. Shell-marl. c. Peat. 



About 50 varieties* of land and fresh-water shells are found in 



Oxide of iroa 48 



Gypsum (sulphate of lime) 32 



Muriate (chloride of potassium and sulphate of 



potash) 20 



100 

 ' A list of them is given by Professor Jones, in his "Lecture on the Geological 

 History of Newbury." 



