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COLLECTOR S MANUAL 



When broken open, fossil clams, brachiopods, and some other 

 fossils found as impressions often yield an inner kernel or lump 

 representing the ancient mud-filling of the inside of the shell. 

 Inexperienced collectors often preserve only this inner filling, 

 which is nearly worthless without the accompanying outer im- 



Fig. 61. — A fossil clam. 



Fig. 62.— A fossil 

 snail. 



pressions. Both kernel and outer impressions must be saved, the 

 latter to determine shape and ornament, the former because of 

 impressions of internal organs and muscular marks. 



In areas where the rocks have disintegrated, leaving fossils free, 

 be sure to use the lens to detect microscopic species such as 

 protozoa or young stages of the larger fossils. If microfossils 

 are noted, brush debris and possible contaminating material from 



