unknown sedimentary rock

This rock sample is unlike any of the others here and has a fibrous and spongy appearance. The materials making this rock are dominantly fine but compacted dried out plant leaves and twig fragments are scattered throughout it. Thus, the rock is non-marine in nature. The brown to light brown color is the norm for this type of rock. These rocks are also soft and can often be broken apart with bare hands. The rock doesn’t taste salty. When a drop of acid is placed on the surface of this rock there is no effect. EDUROCK – EDUCATIONAL VIRTUAL ROCK COLLECTION CC BY(4.0) via sketchfab [https://creativecommons.org/licenses/by/4.0/legalcode]