184 THE ANTARCTIC MANUAL. 
of the “dip ”) and nature of the different strata or masses of rock on 
either side. As, however, he has not this trench or section before 
him, he must observe the dip and nature of the rocks on the surface, 
and take advantage of every bank or cliff where the land is broken, 
always carrying the beds and masses in his mind’s eye to his 
imaginary section. In every case this section ought to be laid down 
on paper, on as nearly as possible the real proportional scale ; copious 
notes should be made, and a large suite of specimens collected for the 
observer's own future examination. The habit of making even in the 
rudest manner sectional diagrams is of great importance, and ought 
never to be omitted ; it often shows the observer palpably, and before 
it is too late (a grief to which every sea-voyager is particularly liable), 
where his knowledge is defective. Partly for the same reason, and 
partly from never knowing, when first examining a district, what 
points will turn out the most important, he ought to acquire the 
habit of writing very copious notes, not all for publication, but as a 
guide for himself. 
It is always a good plan to climb commanding peaks ; the general 
direction of beds, obscure from the lower ground, not unfrequently 
becomes much clearer when they are seen from above. 
When time does not permit of a section across the country being 
examined, or when for any reason, the land surface in general is not 
accessible, attention should be paid to such cliffs as exist, and to the 
sections exposed upon them. Cliffs may often be photographed, and 
the photograph, if not taken from too great a distance, will serve to 
show some of the relations of the beds exposed, but the photograph, 
however good, should be supplemented by notes and sketches, and by 
a record of the true dip of the strata. 
In small islands, a section from side to side should be made, and 
here again photographs will afford valuable aid in preserving a record 
of the geology. In all cases the position of fossiliferous beds, if any 
be found, should be carefully noted. 
The various formations that compose the crust of the earth may 
be divided into (a) sedimentary and (J) crystalline ; and the crystalline 
rocks may be either igneous or schistose. To some extent all these 
different classes of formations occasionally pass into each other; 
sedimentary beds may become cleaved and crystallised; minerals 
may develop in them, until they become foliated, or composed of 
layers of different minerals such as quartz, felspar, mica, or hornblende, 
whilst rocks that are evidently of igneous origin, and injected as veins 
or dykes or irregular masses amongst other strata, pass into granitic 
forms, and granite often takes on the character of gneiss, which is in 
