No. 3.] HUNT — ON CAMBRIAN AND SILURIAN. 281 



HISTORY OF THE NAMES CAMBRIAN AND 

 SILURIAN IN GEOLOGY. 



By T. Sterry Hunt, LL.D., F.R.S. 



It is proposed in the following pages to give a concise account 

 of the progress of investigation of the lower paleozoic rocks during 

 the last forty years. The subject may naturally be divided 

 into three parts : 1. The history of Silurian and Upper Cam- 

 brian in Great Britain from 1831 to 1854; 2. That of the still 

 more ancient paleozoic rocks in Scandinavia, Bohemia, and Great 

 Britain up to the present time, including the recognition by Bar- 

 rande of the so-called primordial paleozoic fauna ] 3. The history 

 of the lower paleozoic rocks of North America. 



I. Silurian and Upper Cambrian in Great Britain. 



Less than forty years since, the various uncrystalline sedimen- 

 tary rocks beneath the coal-formation in Great Britain and in 

 continental Europe were classed together under the common 

 name of graywacke or grauwacke, a term adopted by geologists 

 from German miners, and originally applied to sandstones and 

 other coarse sedimentary deposits, but extended so as to include 

 associated argillites and limestones. Some progress had been 

 made in the study of this great Graywacke formation, as it was 

 called, and organic remains had been described from various 

 parts of it ; but to two British geologists was reserved the honor 

 of bringing order out of this hitherto confused group of strata, 

 and establishing on stratigraphical and paleontological grounds a 

 succession and a geological nomenclature. The work of these 

 two investigators was begun independently and simultaneously in 

 different parts of Great Britain. In 1831 and 1832, Sedgwick 

 made a careful section of the rocks of North Wales from the 

 Menai Strait across the range of Snowdon to the Berwyn hills, 

 thus traversing in a south-eastern direction Caernarvon, Denbigh 

 and Merionethshire. Already, he tells us, he had in 1831, 

 made out the relations of the Bangor group, (including the Llan- 

 berris slates and the overlying Harlech grits.) and showed that 

 the fossiliferous strata of Sneddon occupy a synclinal, and are 

 stratigraphically several thousand feet above the horizon of the 



