PALAEONTOLOGY. 135 



ments can be firmly and securely packed as they are 

 collected, thus preventing their tendency to shake about 

 and scratch one another during further exploration. 



When fossils are extracted from hard rocks, and are 

 detached in lumps or fragments of considerable size, they 

 should only be reduced and roughly trimmed according 

 to the dimensions of the enclosed organism, leaving 

 further manipulation until the specimen arrives at its 

 destination, whether this be in a private or public col- 

 lection, for the final chipping and trimming often 

 requires to be done carefully and leisurely, so as not 

 to break or damage the fossil. A deft and skilful 

 handling of the hammer and chisel is indeed only to be 

 attained by much practice, and the ultimate development 

 of a specimen is always a more or less delicate operation, 

 from which it does not always escape uninjured. 



In chiselling anything out of a soft rock like chalk 

 care should be taken to direct the chisel away from 

 the fossil, and to extract a larger lump than may at 

 first sight seem necessary, otherwise the rock may flake 

 up and destroy the specimen ; when safely extracted, it 

 should then be slightly trimmed, wrapped in plenty of 

 paper, and stowed in the bag or basket. 



With still softer rocks, such as shales, clays, and clayey 

 sands, the specimens can at once be reduced to the 

 proper size and shape by means of the knife ; and then, 

 if carefully conveyed, will need little further attention, 

 unless some preservative, such as gum or gelatine, be 

 required for their ultimate conservation. 



For fossils that are found in loose sands, whether 

 freshwater or marine, and that may be extracted whole 

 and free from the matrix, more care is needed ; they 

 are almost always in a tender and perishable condition, 



