204 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 7, 



often not more than a line apart, but sometimes a quarter of an inch 

 from one another. 



The smaller ones (fig. 4) are in myriads close together, but still 

 plainly in pairs. They occur on the same surfaces with the larger 

 ones, but still oftener are met with in groups ; all of the same size, 

 or nearly so (about the size of a pin's head), and particularly on the 

 red shales before mentioned. On the upper surfaces of the beds they 

 are, of course, depressions (fig. 1) ; on the lower surfaces casts of 

 them project (fig. 4) as tubercles. 



It is a very common thing to meet with them only in the hollows 

 of rippled surfaces, the wave having erased them on the more elevated 

 portions. Sometimes this occurs in the most distinct and marked 

 manner (fig. 1). 



This species appears to be distinct from the so-called A. didymus 

 of the former paper, by the holes being remote, not close together 

 nor parallel to each other. They occur rather higher up in the 

 series too ; but it is, of course, possible that all may be one species. 



Localities. — The small variety has a very wide distribution, as 

 before stated. The larger ones are found in tolerable plenty in Oak- 

 ham Dingle, at Yearling Hill, the Packet Stone, Minton, and at the 

 Light-Spout Waterfall above Church-Stretton. 



It does not appear necessary to insist on the value of such numerous 

 though imperfect vestiges of the oldest fauna known. I am perfectly 

 convinced that the Cambrian rocks contain treasures yet to be dis- 

 covered, and that a holiday spent at the rising town of Church 

 Stretton would be well rewarded, and might produce new facts for 

 science. 



I lately found that burrows similar to the above-described, but of 

 a much larger size, were common in the Stiper Stones of Shropshire ; 

 and these bear the strongest resemblance to the long vertical tubes 

 described by Hall under the name of Scolithus linearis. 



It is almost certain that these are identical ; but, as the name Sco- 

 lithus does not convey any definite meaning, there can be no objec- 

 tion to the term Arenicola, as used by Binney, who first explained 

 the nature of these double holes. Perhaps the termination -ites 

 would make the name more symmetrical with other terms of general 

 import, and Arenicolites might stand for all worm-burrows with 

 double openings, while Scolithus or Scolites might be retained for 

 those which appear to be single tubes or burrows, vertical or hori- 

 zontal*. 



Cololites has long been in use for worm-casts on the surface, and 

 perhaps Helminthites would answer best for those long sinuous tracks 

 upon the surface, usually considered as referable to Annelides. Ver- 

 miculites has been applied to shorter forms f. Some of these, how- 

 ever, are unquestionably trails of small Crustacea, and others of spiral 

 shell-fish. 



* Foralites has been used by M. Rouault for this kind of burrow. See Bull, 

 Soc. Geol. Fr. vol. vii. 1850, p. 742. 

 t Ibid. I. c. p. 744. 



