Ped 



An individual soil aggregate occurring naturally. 



Pedalfer 



The kind of soil in which alumina and iron oxides move 

 downward in the soil profile and in which no accumulation 

 of calcium carbonate occurs, cf. Pedocal, Laterite. 



Pedigree 



A record of the ancestry of an individual. 



Pediment 



A gradual slope covered with scattered rock adjacent to a 

 mountain in semi-arid and arid regions. 



Pedocal 



A type of soil in which a layer of accumulated carbonates 

 occurs, cf. Pedalfer, Laterite. 



Pedogenic 



Refers to effects caused by soil factors. 



Pedology 



The science dealing with soils. 



Pedon 



A Community dependent on the bottom in lakes, cf. 

 Benthos. 



Pelagic 



Refers to the open water of the ocean, lacking associa- 

 tion with the shore or the bottom, cf. Abyssal, Neritic, Ben- 

 thic, Littoral. 



Peneplain 



A land surface worn down by erosion to almost Base 

 level so that most of it appears as a plain. 



Penicillin 



An Antibiotic (q. v.) produced by the mold Penicillin 

 notatum. 



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