Complex sentence: The Maidstone slab was utilized in the first skeletal reconstructions and artistic renderings of "Iguanodon", but due to its incompleteness, Mantell made some mistakes, the most famous of which was the placement of what he thought was a horn on the nose.
Split into simpler sentences: The Maidstone slab allowed the first skeletal reconstructions and artistic renderings of "Iguanodon". As such, he made some mistakes, the most famous of which was the placement of what he thought was a horn on the nose.