LOWER SILURIAN FOSSILS. 37 



A leading objection, with regard to the first 

 fossilil'erous formation (Lower Silurian) is, that 

 it does not solely present animals of the lowest 

 sub-kingdom, as corals and encrinites, but also 

 examples of the two next higher sub-king- 

 doms, the articulata and moUusca, some of the 

 latter being of the highest order, the cephalo- 

 })()ds. The latter particular is what is chiefly 

 insisted upon. 



At the time when I wrote, it was understood 

 that the highest orders of moUusca were not 

 found in the first fossiliferous rocks. Professor 

 Phillips, in 1839, {Treatise on Geology,) said, 

 expressly, with regard to what was then called 

 the Clay-slate and Grawacke system, " No 

 gasteropods or cephalopods are as yet men- 

 tioned in thesfe rocks in Britain ; and we do not 

 feel sufficiently acquainted with the geological 

 age of the limestones of the Ilartz, to introduce 

 any of the fossils of that argillaceous range of 

 mountains." So much as a justification of the 

 view given of the Clay-slate fossils in my first 

 edition. Since then, this formation, as it exists 

 in England, has been found to contain gastero- 



the Natural History of Creation. By the Rey. A. Hume. 

 Liverpool, Whitby, 1845. 



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