The secondary rocks were thought to include interlayered basalts, which Werner thought formed by combustion of buried coal layers.
The Scottish geologist James Hutton (1726-1797) argued that granite and basalt by solidification within the earth (as opposed to precipitating in from oceanwater).
Centuries, the science of geology did not exist as we currently know it.
Obviously people knew about the existence of rocks, and something of their physical properties could clearly be determined.
The use of certain rocks and minerals as resources had of course been taking place since before recorded history (most historians divide up human pre-history into ages based on the use of mineral resources - Stone Age, Bronze Age, Iron Age, etc.).
As sediments are deposited, evidence of these human activities are buried.
Grades/Ages: Grades 6 - 7 Instructor will relate the principals and mechanics of sediment deposition, site dating techniques, the correlation between time and soil levels, and possible site/soil disturbance.
In groups of 3-5 people, students will use soil "keys" to match a known date and soil context to soils on the poster.
Steno's Laws are still used today in stratigraphy - the study of sedimentary strata and reconstruction of the processes that formed them.
Steno's Laws are used for the purpose of relative dating.