What about cellouse makes it ideal for structural support

Due to the strong intermolecular force of attraction in cellulose it provides high strength and support.

Cellulose is a significant polysaccharide since it is the most copious natural compound on Earth. Cellulose is a significant segment of intense cell dividers that encompass plant cells, and it's what makes plant stems, leaves, and branches so solid. It absolutely takes a ton of effort to cause damage to the structure of cellulose.  

Cellulose particles are arranged parallel to one another and are combined with hydrogen bonds. This structures long, link like structures, which join with other cellulose atoms and is the thing that produces such a solid help structure.

i think the miocene epoch spans the time from 23 million to 12 million years ago.

there really is life in the deepest part