BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [12] 



attached, a good i^erfect base of a leaf, or a well-j)reserved portion of 

 the margin. In collecting ferns tlie most valuable specimens are those 

 found in fruit [the small brown clusters of spore-cases on the under- 

 side of ferns] and nothing, no matter how fragmentary, that shows the 

 slightest tendency to fruit-bearing should be discarded." Tree trunks 

 are always important. 



Counterparts, or reverse impressions, should be preserved and kept 

 together, but wrapped separately. Eemove with the trimming ham- 

 mer as much superfluous rock from the specimen as is possible without 

 endangering the safety of the specimen, but never trim closer than to 

 within one inch of the x)lant nor get the pieces so thin that the jarriug 

 of transportation will cause them to break. If a good specimen is acci- 

 dentally broken do not throw it away, but retain all the pieces, wrap- 

 ping them separately and bringing them together in one bundle. 



Plant-bearing clay should be sent to the Museum in bulk, to be 

 broken in the laboratory. 



DIRECTIONS rOR COLLECTING FOSSIL INVERTEBRATES. 



Make large collections. — The first important principle for a collector 

 to observe is to gather large collections from the localities visited. The 

 extent of a collection, of course, will depend upon the abundance of 

 the individuals and species present. Kever restrict yourself to six or 

 a dozen specimens of a common species when hundreds can easily be 

 had. These du]3licates assist in studying the local variation of siiecies, 

 and are also useful in making exchanges. 



Keen eyesight and the expenditure of an abundance of intelligent 

 labor are requisite for the gathering of a valuable collection. It may 

 be the work of many days or weeks to exhaust one localityj and many 

 local collectors have spent a few hours a week for ten, twenty, or even 

 more years in bringing together their unique collections. 



Collecting in hard roclc. — To make a collection from limestone, dolo- 

 mite, sandstone, quartzite, or slate, usually involves considerable work 

 in the breaking and examining of the rock. When such rocks are 

 found in large masses It is well to use a sledge hammer first to reduce 

 the rock to sizes which may be easily broken with the smaller ham- 

 mers. Eocks which never have been subjected to great pressure usu- 

 ally break most readily along the lines of bedding, where fossils are 

 most abundant, therefore the collector should try as much as possible 

 to split the rock along these lines of natural weakness. The peen end 

 of the hammer is best for splitting soft or slaty material, such as shales, 

 slates, or shelly limestones. 



It is bad practice to select a representative collection in the field. 

 Laboratory work nearly always discloses the want of more material for 

 the study of specific variation. The rarer species are also often thrown 

 away by this method of collecting. It is far safer and less expensive 

 to reject specimens in the laboratory than it is to go back to a locality 



