38 THE STORY OF THE EARTH AND MAN. 



he finds a peculiar species of Eozoon, which he namea 

 ~Eowon Bavaricum. In England also the Longmynd 

 groups of rocks in Shropshire and in Wales appears 

 to be the immediate successor to the Upper Lauren- 

 tian; and it has afforded some obscure "worm- 

 burrows/' or, perhaps, casts of sponges or fucoids, 

 with a small shell of the genus Lingulella, and also 

 fragments of crustaceans (Palceopyge). The " Fucoid 

 Sandstones " of Sweden, believed to be of similar 

 age, afford traces of marine plants and burrows of 

 worms, while the Harlech beds of Wales have afforded 

 to Mr. Hicks a considerable number of fossil animals, 

 not very dissimilar from those of the Upper Cambrian. 

 If these rocks are really the next in order to the 

 Eozoic, they show a marked advance in life immedi- 

 ately on the commencement of the Primordial period. 

 In Ireland, the curious Oldhamia, noticed below, ap- 

 pears to occur in rocks equally old. As we ascend, 

 however, into the Middle and Upper parts of the 

 Cambrian, the Menevian and Lingula flag-beds of 

 Britain, and their equivalents in Bohemia and Scan- 

 dinavia, and the Acadian and Potsdam groups of 

 America, we find a rich and increasing abundance of 

 animal remains, constituting the first Primordial fauna 

 of Barrande. 



The rocks of the Primordial are principally sandy 

 and argillaceous, forming flags and slates, without 

 thick limestones, and often through great thicknesses, 

 very destitute of organic remains, but presenting some 

 layers, especially in their upward extension, crowded 



