180 
Fig. 3. 
OVAL. 
Caves. —11. Examine the floors of caves by cuttings from 
the surface as far as the solid rock ; take sections of the 
deposits and note the relics discovered in each stratum. In 
limestone caverns, note the thickness of any stalagmite 
coating upon or beneath the floors. 12. It must be remem¬ 
bered that strata representing vast periods of time may be 
represented by deposits only a few feet or even inches in 
