Illustration of Trilobite (Phacops latifrons) enrolled and open, from 'Organization of the Trilobites' by Hermann Burmeister, appearing in the Ray Society translation of his work published in 1846. The Illustrations and engravings by A. Andorff of Berlin were the finest and most accurate fossil representations of invertebrates up to that time. The work marked a more rigorous approach to the morphology of these groups and a move away from a purely stratiographical approach. The fine lithographic quality of the print owed much to the use of fine Solnhofen limestones that themselves preserved many fine fossils. Fossils such as Archaeopteryx were revealed during quarry work for the raw printing material.