72 Brongniart on Organized Remains. 
1. To collect all the fossil organized bodies which can be 
obtained; especially the distinguishable impressions and re- 
mains of vegetables from coal countries, and beds of wood coal 
and others. The shells, crustacex, madrepores, fishes, §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 utimeaning 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, are often sufficient. 
We may avoid also collecting the inner moulds («des moules 
interieurs”’) of shells, because they are almost invariably inca-’ 
pable of being recognized. 
2, Petrifactions, isolated and detached from their rock, are 
they cannot be separated from the rock, we need not hesr 
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 of 
hinge in view; among madrepores, those on whose surface 
the figures (les étoiles) are distinguishable ; among vegetables, 
those whose leaves are distinctly expanded, (expalmées.) 
3. Upon the objects transmitted it is desirable to have; # 
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 spec 
men of the stratum, or at least of the rock, which contained it 
It is desirable that this rock exhibit remains of petrifaction® 
similar to those found in the stratum from which it has beet 
awn. 
3. The nature of the formation of which this stratum or rock 
composes a part, and specimens of as many of the superior 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 unguestionably found in the same stratum, of * 
