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_, _crustaceæ_, _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 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, are 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 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, 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 specimen 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 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 _unquestionably_ found in the same stratum, or at least in the same formation. The specimens ought to be almost square--about three inches or more on a side, and one and a half thick. 5. It is equally important not to mix petrifactions found in different formations, or in different strata of the same formation; or if they are packed together, to distinguish them by numbers, marks, or labels. When the preceding notices cannot be obtained, the first will suffice.