GENERAL INSTRUCTIONS FOR THE COLLECTION OF SPECIMENS.

Before we proceed on a geological excursion, it is necessary to be provided with suitable instruments to detach specimens from the rocks, and extract fossils from the strata in which we may find them imbedded, and with materials for packing up our treasures, and noting their localities on the spot. For this purpose, the following articles will be found more or less requisite, according to the particular object of the collector:—

1. A hammer of one of the forms figured in Lign. 266. Fig. 3 will be found most generally useful.

2. A leather or strong camlet bag, and one or two of smaller size; the former with strings, or with a strap for the shoulder. If travelling in a carriage, a box or basket may also be provided.

3. Stout and thin paper, and some of a soft kind, for wrapping up specimens.

4. Chip boxes, and raw cotton, wadding, or tow, for the same purpose.

5. String, sealing-wax, and writing paper gummed on one side, for labels to affix to specimens on the spot.

6. A strong pair of gloves, and a pair of eye preservers; common spectacle frames covered with fine black crape will be more agreeable than glass.

7. A measuring tape, a pocket compass, and drawing materials will be required, if the observer intend to note the geological characters of the district.[783]

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]

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.

"3. The specimens ought not to be very small;—about three inches square, and three quarters of an inch in thickness, is a convenient size.

"4. seldom happens that large masses, even of the same kind of rock, are uniform throughout any considerable space; so that the general character is ascertained by geologists, who examine rocks in their native places, from the average of an extensive surface. A collection ought, therefore, to embrace specimens of the most characteristic varieties; and the most splendid examples are, in general, 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.

"5. One of the most advantageous situations for obtaining specimens and examining the relations of rocks is in the sections afforded by cliffs on the sea-shore; especially after recent falls of large masses, t commonly happens that the beds thus exposed are more or less inclined; and in this case, if any of them be inaccessible at a particular point, the decline of the strata will frequently enable the collector to supply himself with the required specimens, within a short distance.

"6. To examine the interior of an unknown country, more skill and practice are required; the rocks being generally concealed by the soil, accumulations of sand, gravel, &c., and by the vegetation of the surface. But the strata are commonly disclosed in the sides of ravines,—in the beds of rivers and mountain-streams; and these, especially where they cross the direction of the strata, may be found, by careful examination, to afford instructive sections.

"The mud and gravel in the beds of rivers and in deltas often contain grains of gold, platina, and other native metals, rubies, sapphires, and other precious stones; and a general knowledge of the rocks of an unexplored country often may be gained from the detritus at the embouchure of a river.

"7. Among the contents of the strata, the remains of organized bodies,—shells, corals and other zoophytes,—the bones and teeth of animals,—wood, and the impressions of vegetable stems, roots, or leaves, &c. are of the greatest importance; affording generally the most marked characters of the beds in which they occur. These should, therefore, be particularly sought after, and their relative abundance or rarity in different situations noticed. The fossils should, if possible, be kept united with portions of the rock or matrix in which they are found; and where they are numerous,—in sand, clay, or any moist or friable matrix,—it is, in general, better to retain a large portion of the whole mass, to be examined afterwards, than to attempt their separation at the time of collecting.

"8. The loose substances which are found above the solid rocks, in the form of gravel, silt, rolled pebbles, &c., should be carefully distinguished from the solid strata upon which they rest. And the more ancient of these water-worn materials, found on the sides or summits of hills, &c., should be distinguished from the recent mud, sand, and gravel, brought down by land-floods or by rivers. The bones and teeth of quadrupeds are not unfrequently found in the more ancient gravel; and the collection of these remains from distant quarters of the globe is an object of the greatest interest to geology.

"9. Besides a note of the locality, there ought, if possible, to accompany every specimen a short notice of its geological circumstances; as, for example, whether it be found in large shapeless masses, or in strata? If in strata,—what are the thickness, inclination to the horizon, and direction with respect to the compass, of the beds? If these cannot be measured, an estimate should always be recorded while the objects are in view. Are they uniform in dip and direction?—curved, or contorted?—continuous, or interrupted by fissures or veins? Is the whole cliff, or mass of strata in sight, of uniform composition?—or does it consist of different kinds of stone? If the strata be different, what is the order in which they are placed above each other successively?

"10. A label, distinctly written, should accompany every specimen, stating its native place, its relative situation, &c., and these labels should be attached to the specimens immediately, on the spot where they were found. This injunction may appear to be superfluous; but so much valuable information has been lost to geology from the neglect of it, that every observer of experience will acknowledge its necessity. It is useful to mark on the labels the day, and even the hour, when each specimen is collected. This, with a corresponding note in the memorandum-book, prevents confusion, and will be found to assist the memory.

"11. A sketch of a coast or cliff, however slight, frequently conveys more information respecting the disposition and relations of rocks, than a long memorandum. If numbers, denoting the situation of the specimens collected, be marked upon such sketches, much time may be saved at the moment of collecting. But in all such cases, the memorandum should be looked over soon afterwards, and labels, distinctly explaining their situation, &c. be attached to the specimens.

"12. The specimens should be so packed, that the surfaces may be defended from exposure to air, moisture, and friction: for which purpose, if strong paper cannot be obtained, dry moss, or straw, or leaves may be employed. Where paper is used for wrapping the specimens, they are best secured by fastening the envelope with sealing-wax.

"Lastly. The collector must not be discouraged, nor be prevented from collecting, by finding that the place which he may chance to visit in a remote situation has not a stinking appearance, or the rocks within his view a very interesting character; since it frequently, and even commonly happens, that facts and specimens, in themselves of very little importance, become valuable by subsequent comparison; so that scarcely any observation, if recorded with accuracy, will be thrown away."

These general instructions will suffice to prepare the reader for an excursion to some known locality, where his researches will certainly be rewarded by many interesting organic remains; and he may be so fortunate as to meet with some rare fossils, and perhaps with one or two that have not previously been discovered; for there is always a chance of finding relics hitherto unknown, even in a cliff or quarry that is daily visited by collectors. And as an old sportsman desirous of inspiring a novice with a love of field sports, takes him at first to preserves where game is plentiful, in like manner I would initiate my reader in the delightful pursuit of collecting Medals of Creation, by conducting him to a spot where these antiquities of nature are scattered about in great profusion and variety.