OF THE CABDONiriiROUS STBATA. 



183 



carboniferous strata have evidently been made by at least two 

 very different kinds of animals. Some of them have been 

 excavated by annelids, whilst others have been made by inha- 

 bitants of univalve and bivalve shells. These trails are often 

 so much alike as to render it difficult to decide as to which of 

 the above-named animals it is that we must attribute their 

 origin. In the Silurian System,* Sir Roderick Murchison 

 has referred certain markings found upon the Cambrian rocks 

 of Lampeter to nereites, myrianites, and nemerites. These 

 fossils Professor Hall, from an examination of many speci- 

 mens of similar fossils found in the United States of America, 

 is more inclined to refer to gasteropodous molluscs and 

 crustaceans analogous to idotea.-\ Without undertaking to 

 determine which of the above learned authors is correct, I 

 shall describe in this communication markings, some of which 

 are the trails of the former inhabitants of shells, and others 

 as equally certain to have been made by worms. 



Mr. William Lee, of Sheffield, in a paper on Fossil Foot- 

 prints of the Carboniferous System, J after describing several 

 varieties of what he terms the tracks of reptiles, states, — " In 

 May last, (1841,) I found upon the moors of FuUwood Head, 

 five or six miles west of Sheffield, some beds of brown sand- 

 stone, covered with foot prints, and also with what appear to 

 be the tracks of worms; (No. 4.) the surfaces are otherwise 

 exceedingly smooth and even. The beds vary from two 

 inches thick to one-sixteenth of an inch, and both the upper 

 and lower surfaces are covered so abundantly with scales of 

 mica, that it may frequently be scraped off with the fingers. 



" The foot prints and worm tracks occur on both sides of 

 the slabs, the indentations being always on the upper surface, 

 and the reliefs on the lower. 



*■ Silurian System, p. 699. 



+ Report of the American Association for the Advancement of Science held at 

 Cambridge in 1849, p. 257. 



X Vol. I. of the Proceedings of the Qeological and Polytechnic Society of the 

 West Riding of Yorkshire, p. 413. 



