252 The Founders of Geology LECT. 



fossiliferous formations, alike in the Old "World and in the 

 New. 



Contenting himself with a mere announcement of his 

 chief results at the first meeting of the British Association, 

 held in York in 1831, Murchison gave a brief outline of his 

 subdivisions of the upper Greywacke to the Geological 

 Society in the spring of 1833. 1 He continued to toil hard 

 in the field, mapping on the ground his various formations, 

 and making careful sections of their relations to each other. 

 Every fresh traverse confirmed the general accuracy of 

 his first observations, and supplied him with further illus- 

 trations of the persistence and distinctness of the several 

 groups into which he had subdivided the greywacke. At 

 the beginning of 1834, he was able to present a revised and 

 corrected table of his stratigraphical results, each formation 

 being defined by its lithological characters and organic 

 remains, and the subdivisions being nearly what they still 

 remain. 2 The Ludlow rocks are shown to pass upward 

 into the base of the Old Eed Sandstone, and downward into 

 the Wenlock group, which in turn is succeeded below by 

 the Horderley and May Hill rocks, followed by the Builth 

 and Llandeilo flags. By the summer of 1835, at the insti- 

 gation of lie de Beaumont and other geological friends, 

 he had made up his mind as to the name that should be 

 given to this remarkable assemblage of formations which 

 he had disinterred from out of the chaos of greywacke. 

 Following the good rule that stratigraphical terms are most 

 fitly formed on a geographical basis with reference to the 

 regions wherein the rocks are most typically developed, he 



Proc. Geol. Soc. vol. i. (1833), p. 474. 

 2 Ibid. vol. ii. (1834), p. 11. 



