HARDWICKE'S SCIENCE-GOSSIP, 



253 



feathery tuft, sometimes brightly coloured, as in those 

 of that little coiled worm which rejoices in such a 

 high antiquity, the Spirorhis. 



Let us take the wandering worms (Errantia) first 

 in order, as they undoubtedly were first in point of 

 appearance in the earlier seas of our globe. The 

 names assigned to the commonest of the tracks and 

 trails believed to have been left by them are borrowed 

 in most instances from modem genera; thus we have 

 Phyllodocitcs, Alyrianites, Crossopodia, Arenicolites, &c. 

 The markings we have to explain are of two kinds, 

 burrows and trails. The sea-worms making the 

 former were doubtless of similar habits to our 

 common lob-worm {Arenicola piscatoriitii) and the 

 generic name of Arenicolites at once indicates this. 



their eyes open to the periodical mending of the roads 

 and causeways of the towns in which they live. In 

 the neighbourhood of Manchester'and Sheffield the 

 newly-laid flags are often seen ripple-marked and 

 worm-tracked or worm -burrowed. The Cambrian and 

 Silurian sandstones afford similar'evidence of shallow 

 water deposition. In the Stiper Stones (Upper 

 Cambrian) both casts and burrows are abundant. In 

 the Bangor slate quarries the markings are called 

 Chondrites, from the original belief that they were 

 impressions left by sea-weeds, but we favour the 

 theory of their annelid origin. In the slate quarries 

 near Douglas, in the Isle of Man, there may be- 

 frequently found the tracks of two kinds of sea- 

 worms, Nereis and Neviertites. As before remarked,. 



Fig. 183. — Teniacidites annulaius. 



The Cambrian rocks of Bray Head, near Dublin, 

 have long been famous for the occurrence of markings 

 left by an ancient burrowing worm, named by Dr. 

 Kinahan Histioderma Hiberniciim, associated with 

 the zoophyte Oldhamia. The tubular casts of these 

 worm-holes may be obtained. The upper part swells 

 out into a trumpet-shaped mouth, frequently very 

 prettily marked. The holes of Arenicolites sparsns 

 and Arenicolites didyiniis are in pairs, and are found 

 in the same beds as Histiodcrina. 



The flag-stones obtained from the millstone grit 

 formation in Lancashire and Yorkshire have their 

 surfaces frequently knobbed irregularly with the casts 

 of worm-furrows. Young geologists who often sigh 

 for opportunities to geologise abroad should keep 



Fi^. -iZ^. — Serpnla with tentacles expanded (recent^ 



^'^j k 



Fig. 1S5. — Kereis (recent). 



however, the Longmynd rocks afford by far the largest 

 number of evidences of ancient sea-worms. In the 

 Wrekin the quartzite beds yield Arenicolites Urico- 

 nicnsis, which may be considered the oldest known 

 British fossil. The rocks of St. David's contain both 

 Arenicolites and Serpulites, In the Skiddaw slates, 

 near Keswick, Cumberland, ten species of the remains 

 of fossil-worms have been catalogued, among which 

 Scolithtis and HelniintJwlithiis are the most abundant.. 

 One remarkable species has been named Stellascolites. 

 In many parts of Great Britain the lower Carboni- 

 ferous rocks possess most abundant traces of worm- 

 tracts. Any tourist who has visited the magnificent 

 Cliffs of Mohr, in county Clare, Ireland, cannot fail 

 to have noticed the dark slaty flags of the district,. 



