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 throughout 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, IN GENERAL, NOT THE MOST INSTRUCTIVE.
Where several specimens are taken in 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 seashore; especially after recent falls of large masses.

It 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 specimens he wishes for, within a short distance.