BRITISH AVONIAN CONODONT FAUNAS 275 
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SERIES ————_——_— 
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CEMENTSTONE GROUP 
——+——_— MAIN ALGAL ‘ 
Abundance factor = Total weight of sample 
Total no. of specimens in kilograms 
Total weight of sample 
Fic. 91. Lithological section of the Lower Algal Limestone “ Series ’’ of Harden Burn, 
Roxburghshire, (NY 517907) showing the abundance factor for each sample and the 
weight of each sample dissolved. 
