RECENT ADDITIONS TO ANCIENT SEDIMENTS. 359 



In that monograph we find a record of the beds as occur- 

 ring in Britain, Scandinavia, Russia and various parts of 

 North America. Since its publication other areas have been 

 shown to contain a development of the rocks possessing 

 this fauna. Their existence in Britain had been previously 

 shown by Lapworth (8), who has since, however, described 

 the included fossils in greater detail (9). Another British 

 area where Olenellus beds occur is in the Scottish Highlands. 

 Olenellus has been detected in Ross-shire by Messrs. Peach 

 and Home (10). Abroad we have now a detailed account of 

 the beds of this age by Bornemann in Sardinia (11), and 

 fossils which appear to appertain to the Olenellus zone have 

 been described by Dames in China (12) and Foord in 

 Australia (13), whilst Waagen records the discovery of Olen- 

 ellus by Middlemiss in India (14). Hicks also claims that 

 the Caerfai beds of South Wales should be referred to the 

 Olenellus zone (15). 



Of the higher Cambrian beds little need be said. Our 

 knowledge of their local development in various areas and 

 of their included faunas has steadily increased. In our 

 own country two important discoveries have been recently 

 made, viz., the detection of Conocoryphe in the green slates 

 of Bethesda by Dobbie (16), and the discovery of 

 Paradoxides above the Olenellus beds of Shropshire by 

 Groom (9). In foreign countries much progress has been 

 made in the detailed working of the Cambrian rocks, with 

 the result that they can now be largely grouped into defi- 

 nite zones characterised by special forms of life. Amongst 

 the valuable work which has been done may be mentioned 

 that of Brogger in Norway (17), Tullberg in Sweden (18), 

 and that which Matthew has published during many years 

 on the fauna of the St. John group in the Transactions of 

 the Royal Society of Canada. 



3. THE ORDOVICIAN AND SILURIAN SYSTEMS. 



As the character of the work which has been recently 

 done amongst the rocks of these two systems is essentially 



