Complex sentence: Some fossile seem to show what may be a hardened area on the top (bottom on the drawing) of its hump: this may have been to protect the top of its hump if it hit a rock overhang during this escape action.
Split into simpler sentences: Some fossile seem to show what may be a hardened area on the top (bottom on the drawing) of its hump. This may have been to protect the top of its hump if it hit a rock overhang during this escape action.