wiki Word: stratigraphy

                                       strah  tig  rah  fee

   The word stratigraphy taken apart is divided into to words: stratus which means layers, and ography which means the describing and mapping of something. Therefore, stratigraphy is the describing and mapping of layers.

     Stratigraphy mostly refers to the law of superposition, soil, and geological strata with archaelogical materials in order to determain the age of the layers. Stratigraphy is used to map the surface of Mars and determain age rank of crevices, supposable waterways, sedemental rocks and other features to see how long ago they were formed and if they have any evedence of life forms under other strata. The stratigraphal layers can be made from all sorts of rocks and fossils which can help determain age rank of the layers or the fossils. 

the previous picture came from-

 .http://www.biota.org/conf97/jpgs/shale1b.jpg

This term applys to our class because we have been studying and mapping the surface on Mars and determaining which layers formed first and the age of the mark in comparison to another. We also did an observation project and saw how erosion sedements can create strata and how the layer that is the lowest is the oldest. 

http://www.biota.org/conf97/jpgs/shale1b.jpg 

http://id-archserve.ucsb.edu/Anth3/Courseware/Chronology/04_Stratigraphy.

http://en.wikipedia.org/wiki/Stratigraphy