Siltstone is a fine grained
clastic sedimentary rock.
It has a silt-sized
which is between this of sandstone
It contains quartz,
and coal and plant fossils.
is present, the rock is flaggy.
By James St. John via Flickr.com
It is often a durable and hard rock.
can have internal layering, ripple marks, dessication cracks and cross
bedding, but it does not break easily into layers.
By Rupert Ganzer via Flickr.com
It is most often
grey but can
It is much less common than sandstones or shales,
and it does not form thick deposits as do