472 DIllECTIONS FOE COLLECTING FOSSILS. 



purpose of ascertaining whether bones . of different animals 

 are found at different depths, to extract them from the lower 

 as well as the higher portions of the fissure, and carefully to 

 note the succession of the several specimens thus obtained. 



10. "Where petrifying sources, as they are called, occur, or 

 waters impregnated with calcareous and other matter, thrown 

 down and consolidated into masses enveloping branches and 

 other parts of vegetables, &c., the collector should, together 

 with specimens, obtain any information within his reach, 

 relative to the condition under which such deposits have been, 

 or continue to be formed. In general it is also desirable 

 chemically to examine such, and other waters remarkable for 

 any striking peculiarity. They may readily be transmitted 

 in clean, strong bottles tightly closed, sealed, and labelled. 



11. In tracts of country where volcanos are in action, 

 especially if still unexplored by geologists, not specimens 

 only should be collected, but likewise all the historical data 

 that can be obtained relative to the different eruptions and 

 other phenomena connected with them ; and all such 

 circumstances should be noted as in any manner relate to the 

 nature and appearance of those volcanos their situation, 

 form, craters, &c.; together with every particular concerning 

 the lava-currents, their heat before consolidation, their 

 direction, &c., and perfect suites should be formed of the 

 various volcanic ejections. In endeavouring to detach 

 specimens from a current of lava, the collector should not 

 confine himself to the upper crust of scoria ; but should 

 likewise obtain fragments from the middle and lower 

 beds. Ashes and other pulverulent volcanic matter are 

 best preserved in strong bottles. "Where they are found to 

 enclose organic or other objects, these should be particularly 

 attended to. 



12. With regard to certain other rocks, to which the term 

 trappean is applied, and which are now likewise generally 

 considered as igneous, or as having been propelled, when in 

 a state of fusion, through various rocks which they overlie, 

 the collector, under the supposition that he is not altogether 

 unacquainted with some of these rocks, such as basalt and 

 porphyry, is desired to direct his attention to any alteration 

 that may be observable in the condition of the strata in 

 immediate contact with them. These conditions relate to 



