HANDBOOK OF FOSSILS. 93 



complete the list of more remarkable fossils. The subdivisions 

 of the Cambrian rocks will be found in the table on p. 16. 



6. Pre-Cambrian. Near St. David's Head and some other 

 places in Wales, in Anglesea, Shropshire, etc., some yet older 

 rocks have been found. They are probably for the most part of 

 volcanic origin, but they have been so much changed since they 

 were first deposited, and as hitherto no fossils have been found 

 in them, little is known concerning them. 



Parts of the western coast of Northern Scotland and the Heb- 

 rides are composed of a crystalline rock called Gneiss, and sup- 

 posed to be the oldest member of the British strata. No fossils 

 have been found in it. 



Skull of Deinotherium giganteum, a huge extinct animal, related to 

 the elephants (from the Miocene of Germany). 



VOLCANIC ROCKS. Although there are fortunately no vol- 

 canoes to disturb the peace of our country at the present day, 

 there is abundant evidence of their existence in the past. Not 

 only are some of the beds, especially those of Paleozoic age, 



