Brongniart on Organized Remains. 73 



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 forma- 

 tion ; 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. 



In order to collect the petrifactions, and to render them 

 useful, it is not necessary to know them, nor to be perplexed 

 to find them out ; nor to be afraid of sending objects already 

 known or of Uttle note. A part of the preceding indications, 

 connected with the most common petrifactions, will always ren- 

 der them useful. The important point then is, not to mix 

 those which are found separate, nor to separate those which 

 are found associated in the same stratum. 



This is easily attained, by designating by a common number, 

 letter, or any sign whatever, one particular formation or stra- 

 tum, and by marking with the same sign all the petrifactions 

 which are evidently found together. 



The labels designating the place or the geological situation, 

 may be placed in the papers which envelope the specimens, or 

 a number, referring to an explanatory catalogue, may be at- 

 tached to each specimen. 



As far as possible, it is necessary to stick the labels or num- 

 bers to the pieces, by pasting ; and the surest way is, to write 

 upon the piece itself, 1st, the place where it is found ; 2d, the 

 number by which it is indicated in the historical notes above 

 requested. 



If there is not time to make out as ipany numbers or labels 

 as there are pieces, it will be sufficient to unite in one box or 

 packet all the petrifactions of one particular stratum, and to 

 designate them by a general label. 



It is necessary to pack the shells and other fragile pieces in 

 separate boxes, and to wrap each piece in a separate paper. 



M. Brongniart cannot allow himself to prefer such requests, 

 except under the express condition, that a memorandum of all 



