APPENDIX. 



No. II. 



INSTRUCTIONS FOR COLLECTING GEOLOGICAL SPECIMENS* 



It so often happens that specimens sent from distant places, by persons unpractised in geology 

 fail to give the instruction which is intended, from the want of attention to a few necessary pre- 

 cautions, that the following directions may perhaps be useful to some of those, into whose hands 

 these pages are likely to fall. It will be sufficient to premise, that two of the principal objects of 

 geological inquiry, are, to determine, — 1st, the nature of the materials of which the earth is com- 

 posed ; and, 2ndly, the relative Order in which these materials are disposed with respect to each 

 other. 



1. Specimens of rocks ought not, in general, to be taken from loose pieces, but from large 

 masses in their native place, or which have recently fallen from their natural situation. 



2. The specimens should consist of the stone unchanged by exposure to the elements, which 

 sometimes alter the characters to a considerable distance from tlie surface. — Petrifactions, however 

 are often best distinguishable in masses somewhat decomposed ; and are thus even rendered visible, 

 in many cases, where no trace of any organized body can be discerned in the recent fracture. 



3. The specimens ought not to be too small. — A convenient size is about three inches square, 

 and about three-quarters of an inch, or less, in thickness. 



4. It seldom happens that large masses, even of the same kind of rock, are uniform through- 

 out any considerable space ; so that the general character is collected, by geologists who examine 

 rocks in their native places, from the average of an extensive surface : — a collection ought therefore 

 to furnish specimens of the most characteristic varieties ; — and the most splendid specimens are, i?t 

 gtneral, not the most instructive. Where several specimens are taken from the same place, a series of 

 numbers should be added to the note of their locality. 



• From the Appendix to Captain P. P. King's " Narrative of a Survey of tlie Inter-tropieal and Western 

 Coast of Australia by William Henry Fitton, M.D., F.R.S., V.P.G.S. 



