[783] On the construction of geological maps and sections, see the Appendix to De la Beche’s Geological Observer.
8. A good geological map of the country; if this cannot be procured, the best geographical map.
9. A strong double-bladed knife; one or more chisels.
10. A pocket set of single lenses of three powers, to examine minute objects; blank memorandum books.
Such are the articles that will be required for a geological excursion intended to comprehend a scientific examination of a district; but for a mere trip to collect fossil remains, several may be dispensed with. Some years since, an eminent geologist, Dr. Fitton, drew up some excellent instructions for collecting specimens, for the use of the party employed under Captain King to survey the Western coast of Australia; by permission of the author, they are here subjoined.[784]
[784] For the collection of rock specimens, and for the mode of observing the phenomena of physical geology, Sir H. De la Beche s instructive volume, "How to Observe," should be consulted.
INSTRUCTIONS FOR COLLECTING GEOLOGICAL SPECIMENS.
"It may be proper 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 composed: and, 2dly, the relative order in which these materials are disposed in relation 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 depth from the 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.