The Lycopsids were the largest plants of the Mazon Creek area and composed up to 85% of the
eventual coal composition. Many grew to around 100-feet tall with a trunk base three feet in
diameter. Their growth was very rapid, reaching their full height in as little as five years and
living up to 15. They differ from modern trees in that they contained very little wood, instead
using their bark for support. There were about 10 types, all of them spore-bearing.