i68 



OUR COMMON BRITISH FOSSILS, 



Lower Carboniferous rocks near Settle, in the Valley 

 of the Ribble. 



No doubt most, if not all, of these tracks were 

 made by worms like our common Nereis. This had 



long been suspected before 

 Dr. Hinde, by dint of great 

 patience, discovered annelid 

 jaws in the Silurian shales 

 at Ludlow, Much Wenlock, 

 Iron Bridge,'Stoke Edith, and 

 elsewhere. These are figured 

 in his paper on the subject 

 read before the Geological 

 Society. The largest of the 

 annelid jaws he found so 

 plentifully did not exceed 

 one-fifth of an inch. Dr. 

 Hinde has proved that these jaws differed as much 

 among themselves so far back as the Silurian period 



as they do now — a 

 plain indication of the 

 antiquity of the tribe. 

 Worms which form 

 tubes cannot of course 

 make tracks, but they 

 leave evidences of 

 their existence behind 

 them in the fossil tubes they once inhabited. These 

 sometimes form strata of no inconsiderable thick- 



Fig. 136. — Extremity of Tube of 

 Histioderma Hibernicum. 



Fig. 137. — Serpula with tentacles expanded 

 (recent). 



