90 HISTORICAL PALAEONTOLOGY. 



(8) 'Acadian Geology.' Dawson. Pp. 641-657. 



(9) " Guide to the Geology of New York," Lincklaen ; and "Contribu- 



tions to the Palaeontology of New York," James Hall. ' Four- 

 teenth Report on the State Cabinet.' 1861. 



(10) ' Palaeozoic Fossils of Canada.' Billings. 1865. 



(11) 'Manual of Geology.' Dana. Pp. 166-182. 2d ed. 1875. 



(12) "Geology of North Wales," Ramsay; with Appendix on the 



Fossils, Salter. 'Memoirs of the Geological Survey of Great 

 Britain,' vol. iii. 1 866. 



(13) " On the Ancient Rocks of the St David's Promontory, South Wales, 



and their Fossil Contents." Harkness and Hicks. 'Quart. 



Journ. Geol. Soc.,' xxvii. 384-402. 1871. 

 n the Tre 



(14) "On the Tremadoc Rocks in the Neighbourhood of St David's, 

 South Wales, and their Fossil Contents." Hicks. 'Quart. 

 Journ. Geol. Soc.,' xxix. 39-52. 1873. 



In the above list, allusion has necessarily been omitted to numerous 

 works and memoirs on the Cambrian deposits of 'Sweden and Norway, 

 Central Europe, Russia, Spain, and various parts of North America, as 

 well as to a number of important papers on the British Cambrian strata by 

 various well-known observers. Amongst these latter may be mentioned 

 memoirs by Prof. Phillips, and Messrs Salter, Hicks, Belt, Plant, Horn- 

 fray, Ash, Holl, &c. 



CHAPTER IX. 

 THE LOWER SILURIAN PERIOD. 



The great system of deposits to which Sir Roderick Murchi- 

 son applied the name of * Silurian Rocks " reposes directly 

 upon the highest Cambrian beds, apparently without any 

 marked unconformity, though with a considerable change in 

 the nature of the fossils. The name "Silurian" was originally 

 proposed by the eminent geologist just alluded to for a great 

 series of strata lying below the Old Red Sandstone, and occu- 

 pying districts in Wales and its borders which were at one 

 time inhabited by the "Silures," a tribe of ancient Britons. 

 Deposits of a corresponding age are now known to be largely 

 developed in other parts of England, in Scotland, and in Ire- 

 land, in North America, in Australia, in India, in Bohemia, 

 Saxony, Bavaria, Russia, Sweden and Norway, Spain, and in 

 various other regions of less note. In some regions, as in the 

 neighbourhood of St Petersburg, the Silurian strata are found 

 not only to have preserved their original horizontally, but also 

 to have retained almost unaltered their primitive soft and inco- 

 herent nature. In other regions, as in Scandinavia and many 



