558 Geological Instructions. ‘[Ocr. 
be examined carefully when brought to England, than that any separation of the 
shells should be attempted at the time of their collection. This injunction, however, 
does not apply to those cases in which the shells fall readily from their surrounding 
matrix ; but, in this event, great care must be taken of the petrifactions, by rolling 
them in paper, or some soft material. 
3. If several varieties of stone are seen in the same cliff or quarry, and-particu- 
larly if they contain any petrifactions, specimens of each should be taken, and 
numbered according to their order of succession; marking the uppermost No. 1., 
and thence descending with Nos. 2, 3, &c., making as correct an estimate as time 
will permit of the thickness of the beds. None of these specimens need be more 
than 3 in. square, and one and a half or two thick. (fig. 1.) i 
4. If the rocks are stratified, that is, divided into beds, state whether they are 
horizontal, inclined, or twisted. If inclined, observe pretty nearly at what angle, 
and to what point of the compass they dip; if twisted, a sketch, however slight, 
is desirable. —N.B. The true dip can seldom be ascertained without examining 
the beds on more sides than one. (fig. 2.) 
_ 5. One kind of rock is occasionally seen to cross and cut through the beds of 
another. In such a case, observe whether the beds are in the same plane on each 
side of the intruding rock ; if not, mark the extent of the disturbance, and also if 
there be any difference in the nature of the stone of which the beds are composed, 
at those points where they touch the intruding rock. Take specimens from the 
junction, and make a sketch of it. (fig. 3.) 
6. Where there are wells, get a list of the beds sunk through in digging them ; 
specifying the thickness of each stratum in its order, from the surface downwards, 
7. In volcanic districts, procure a list of the volcanoes now or recently in action, 
and of those which are extinct ; stating their position, their distance from the sea 
or any great lake ; the extent, nature, and, if possible, the age, of particular streams 
of lava, or the relative age of different streams: also whether the lava currents 
conform to the valleys, or are seen at different heights above the present rivers ; 
and also if any gravel beds be discoverable beneath the streams of lava. (fig. 4.) 
8. Note the names of all places known to contain coal, bitumen, salt, alabaster, 
metallic ores, or any valuable minerals, specifying their extent, and the nature of 
the rocks in which they occur; but do not bring away large quantities of iron ore, 
Spar, salt, &c. 
9. In cases of coal-pits, specimens of the coal itself and of the beds passed 
through to obtain it (especially when plants have been found) will be valuable. 
State whether limestone, iron ore, or springs of bitumen are found near the coal; 
and if the limestone contains shells, collect abundance of them. 
10. Make particular inquiries whether, in digging gravel-pits, or beds of sur- 
face clay, mud, and sand, the workmen are in the habit of finding any bones of 
quadrupeds ; and obtain as many of them as possible, selecting particularly teeth 
and vertebre. 
11. Search also for bones in cracks of rock, and in caverns. In the latter, the 
lowest pits or hollows are most likely to contain bones; and if the solid rock be 
covered with a crust.of spar or marl, break through it, and dig out any bones, horns, 
or pebbles from beneath. (fig. 5.) 
12. Observe if the surface of the country be strewed over with large blocks of 
stone ; remark whether these blocks are angular or rounded, and whether they are 
