172 OUR COMMON BRITISH FOSSILS. 



in the Upper Silurian rocks near Kendal ; and the 

 student will find a capital collection of them in the 

 museum of that town. A more delightful neighbour- 

 hood for fossilizing than Kendal can hardly be found 

 in England, or a more varied one. I have seen 

 Serpiilites more than a foot long in the deserted 

 Silurian quarries near Ledbury. 



The Secondary rocks contain true Serpula^ and 

 these fossils are not without a special value to the 

 physical geologist. Some of them may be found 

 sprawling over the interiors of bivalve shells, or 

 covering the naked tests of sea-urchins — in both 

 instances plainly informing us that the life-and-death 

 conditions of the ancient sea-floors were very like 

 those of our day. Moreover, the occurrence of these 

 creeping worm-tubes over the dead tests of such sea- 

 urchins as Ananchytes — one of the commonest in 

 the Chalk — shows us that the chalky ooze must have 

 been forming very slowly, or it would have buried up 

 the dead animals before the sea-worms had managed 

 to spread their tubes over and about them ! 



We frequently get the tubes of Serpula attached to 

 fossil bivalves in the Lias and Oolitic rocks : some- 

 times they form dense and tortuous masses, as in the 

 Oolitic marlstone near Banbury, and in the well- 

 known " Serpula-bed " at Blue Wyke Scar, near 

 Scarborough — where the geologist may obtain abun- 

 dant fossils, and enjoy some of the finest coast scenery 

 in England at the same time. The tabular Iron- 



