FOSSIL INVERTEBRATES AND PLANTS 109 



be examined with the lens to determine if cellular structure is 

 preserved. If none is evident and the wood structure is com- 

 pletely obliterated by mineral substance, it is worthless. Speci- 

 mens having cellular structure should be saved, in the form of 

 examples measuring at least 2 inches on the side. 

 Broken specimens, if good, may be taken for mending in the 



Two ammonoids. 



laboratory. In the field hold the broken pieces together lightly 

 and make marks across the break (but not on the fossils), which 

 can be matched readily in the laboratory. Wrap the pieces 

 separately but bundle the wrapped pieces together. 



A label giving the exact location and stating the formation 

 from which it came should accompany every specimen or collec- 

 tion when possible. However, some regions have not been studied 

 enough to give this geological information. The collector then 



