914 



Transactions ofihe Society. 



4th. A portion from the middle of the deposit. 



5th. A portion from the lowest part of the deposit. 



All these collections I kept carefully separated, and having 

 cleaned and examined them, I have arranged them in five columns, 

 marking the relative abundance of each species. One asterisk, marks 

 very rare; two asterisks, rare; three asterisks, common; four 

 asterisks, abundant. 



List op Diatomacejs from Llyn Arenig Bach. 



