i Guettard's Paleontology 25 



to modern crabs and prawns. They are well-marked 

 trilobites, and his figures of them are so excellent that the 

 genera, and even in some cases the species, can easily be 

 made out. His representation of the large Illcenus of 

 these Lower Silurian slates is specially good. His memoir, 

 read before the Academy in 1757, and published in 1762, 1 

 is thus a landmark in geological literature, for it appeared 

 eighty years before Murchison's Silurian System made 

 known the sequence and abundant organic remains of the 

 Silurian rocks of "Wales. 



Guettard's labours in palaeontology ranged over a wide 

 field. We find him at one time immersed in all the details 

 of fossil sponges and corals. At another, he is busy with 

 the mollusca of the Secondary and Tertiary rocks. Fossil 

 fishes, carnivora, pachyderms, cetacea all interest him, 

 and find in him an enthusiastic and faithful chronicler. 

 His descriptions are not of the minutely systematic and 

 technical order which has prevailed since the time of 

 Linnaeus. Yet some of his generic names have passed 

 into the language of modern palaeontology, and one of 

 the genera of Chalk sponges which he described has been 

 named after him, Guettardia. He had within him the 

 spirit of the true naturalist, more intent on understanding 

 the nature and affinities of organic forms than on adding 

 new names to the scientific vocabulary. His descriptions 

 and excellent drawings entitle him to rank as the first 

 great leader of the palaeontological school of France. 



1 "Sur les Ardoisieres d'Angers," Trans. Acad. Roy. Sciences, 1762, 

 p. 52. The Dudley trilobite of the Upper Silurian limestone of England 

 had been figured and described by Lhuyd in his Lithophylaeii Britannici 

 Iconographia (1699), Epist. i. p. 96 and PI. xxii. ; a figure of it was sub- 

 sequently given in Phil. Trans. 1754, PL xi. Fig. 2. 



