72 Brongniart on Organized Remains. 



1 . To collect all the fossil organized bodies which can be 

 obtained ; especially the distinguishable impressions and remains 

 of vegetables from coal countries, and beds of wood, coal, and 

 others. The shells, crustacece, madrepores, Jishes, &c. It is 

 not necessary that these bodies should be either large or entire, 

 but they must be sufficiently characterized to be capable of 

 being recognized. 



It is useless to transmit large unmeaning pieces, which are 

 recommended only by their size — such as large ammonites — 

 large madrepores.^ — large pieces of petrified wood — fragments 

 of the one, or small individuals of the other, arc often sufficient. 

 We may avoid also collecting the inner moulds (" des moules 

 interieurs") of shells, because they are almost invariably 

 incapable of being recognized. 



2. Petrifactions, isolated and detached from their rock, are 

 the most convenient in the determination of species ; but when 

 they cannot be separated from the rock, we need not hesitate 

 to send them engaged ; it is sufficient if a portion large enough 

 for discrimination is visible. 



Among shells, those are preferable which have the mouth 

 or hinge in view ; among madrepores, those on whese surface 

 the figures (les etoiles) are distinguishable ; among vegetables, 

 those whose leaves are distinctly expanded, (expalmees.) 



3. Upon the objects tramsmitted it is desirable to have, at 

 least in part, the following notices : 



1. The exact place from which the object comes: this is 

 the most important circumstance, and the easiest to obtain. 



2. The kind of formation in which it is found, and a speci- 

 men of the stratum, or at least of the rock, which contained it. 

 It is desirable that this rock exhibit remains of petrifactions 

 similar to those found in the stratum from which it has been 

 drawn. 



3. The nature of the formation of which this stratum or 

 rock composes a part, and specimens of as many of the supe- 

 rior and inferior strata as can be obtained, designating the 

 order of superposition of the strata. 



4. It is important to designate, by the same mark, all the 

 petrifactions unquestionably found in the same stratum, or at 



