Sedimentary rocks are divided into three different categories: Chemical, detrital and biogenic. Chemical rock ... Sandstone and Shale and are some examples of sedimentary rocks.

Sedimentary ... remains of other rocks (known as 'clastic' sedimentary rocks); by the accumulation and the consolidation of sediments; by the deposition of the results of biogenic activity ...

A team led by the University of Tokyo found graphite in Labrador, Canada that they think is biogenic ... These researchers found graphite in sedimentary rocks. Tsuyoshi Komiya of the University ...