of Geological Specimens. 443 
particularly 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. (fg. 108.) 
108 cia | / 
Cer cug tg 
Bones 7 ft. 
Plants 5 ft. 
Shells 10 fe. 
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 ascer- 
tained without examining the beds on more sides than one. (jig. 109.) 
109 
Sa 
Horizonial Beds. Inclined Beds, Dip 60°. Twisted Beds. 
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 
mtruding rock. Take specimens from the junction, and make a sketch of 
it. (jig. 110.) 
110 Fault, or Dislocated Beds. 
Fault, or Distocatcd Beds. 
Rock A cutting through other rocks, 
51D S1yB Go fOr 
MID Gr Eto 
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8. £0.) 39). 8472) Go <8: 
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 sur- 
face 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 dis- 
tance 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. 111.) 
GG 2 
