BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [46] 



number in a book, kept for this purpose, is to be recorded all the informa- 

 tion at hand concerning the specimens, such as locality, collector, hori- 

 zon, etc. The same number will be placed on all the specimens that 

 were obtained by the same collector, at the same place and time. They 

 may then be moved about and grouped in various ways during the time 

 they are being studied and yet can always be identified by referring to 

 the catalogue. The labels should be attached to the specimens with 

 strong glue, and care should be taken not to put them in a place that 

 will obscure an impression j)reserved upon the rock or be in the way of 

 any excavation that it may be desirable to make on the specimen. 



It will often happen that in specimens brought in from the field a 

 larger or smaller portion of the leaf or vegetable fragment will be still 

 covered up in the matrix. With a number of small chisels and a light 

 hammer this obscuring material can be entirely removed, thus exposing 

 oftentimes a perfect leaf or other organ. The chisels should be sharp, 

 of various sizes and made of the best tool-steel, as chipping many kinds 

 of rock will be very hard on them. With a little experience the over- 

 lying material can be skillfully removed without injury to the speci- 

 men. The size of the hand specimens can also frequently be advan- 

 tageously reduced without injury to the impression. For reducing the 

 size of specimens a small hammer with square faces should be used. 

 By holding the specimen firmly in the left hand and delivering a sharp, 

 quick blow with the hammer a small fragment may be removed with- 

 out breaking the specimen. In this way the specimen may be reduced 

 to almost any desired size or shape, so long as it does not interfere with 

 the impression preserved upon it. 



The specimens of fossil plants after they have been prepared and 

 studied should be kept in trays of suitable depth in a cabinet prepared 

 for the purpose. 



O 



