HANDBOOK OF FOSSILS. 89 



minuta) occurs in the upper beds ; whilst now and again the 

 teeth and bones of some strange amphibians (Labyrinthodon^ or 

 the impressions of their feet 

 (Cheirotheriuni) where they 

 crawled on the then soft mud of 

 the foreshore, are found. The 

 Trias is divided into Upper Trias 

 or Keuper, and Lower Trias or 

 Bunter. The middle beds 

 (Muschelkalk), which are found 

 in Germany, where they contain 

 plenty of fossils, are wanting in 

 this country. In the lower beds 

 of the Keuper, layers of rock 

 salt, sometimes of great thick- 

 ness, occur, whilst casts (called 

 pseudomorphs) of detached salt- 

 crystals are found abundantly in 

 the sandy marls. Northwich, 

 Nantwich, Di-oitwich and several 

 other towns in Cheshire and 

 Worcestershire, are famed for their salt works, the salt being 

 either mined or pumped up as brine from these beds. 



PALAEOZOIC OR PRIMARY. Beds of this age generally possess 

 a more crystalline and slaty structure than any of those already 

 mentioned, are usually more highly inclined and disturbed, and 

 form for the most part more elevated ground. They are the 

 principal store-houses of our mineral wealth, containing as they 

 do coal, iron, and other metals. The Palaeozoic rocks are 

 found in England to the north and west of the secondary series, 

 beneath which they disappear when traced to the south-east. 

 Wales, and the greater part of Scotland and Ireland, consist of 

 beds of this age. 



I. Permian. Under this term are included beds of red sand- 

 stones and marls, closely resembling those of Trias, and like 

 them containing but few fossils, as well as a very fossiliferous 

 limestone, known as the Magnesian Limestone, from the 

 abundance of magnesia it contains. A pretty polyzoan 

 (Femstella t-etiformis), a spiny brachiopod (Productns IiorHdus), 

 various genera of fish, chiefly found in a marl state underlying the 

 limestone, some Labyrinthodonts and plant remains, are the prin- 

 cipal forms met with in this formation. 



2. Carboniferous. This, from a commercial point of view, is 



