NOTES ON THE FOSSILS OF ONTARIO. 139 



Hocks : Abstract, Proceedings of the Royal Society, No. 144, 1873.) 

 for a group of fossils of constant occurrence in the sandy and- shaly 

 sediments of the Palaeozoic Rocks, and consisting of the filled-up 

 biuTows of marine Annelides, more or less nearly allied to the existing 

 Lob-worms. These burrows are not vertical as in ScoUthus, Ilistio- 

 ■derma, Arenicolites and the like, but they are irregular in their 

 course and direction, sometimes being more or less horizontal, then 

 running obliquely, and then perhaps taking a vertical direction for 

 a space. The actual burrows themselves are not now preserved to 

 us, but we have in their stead the fillings of the burrows, consisting, in 

 general if not universally, of the sand and silt which has actually been 

 passed by the worm through its alimentary canal. The fossils referred 

 to Planolites consist, therefore, of casts of the burrows of marine 

 worms formed by the ejecta of the animal, and they appear usually 

 in the form of cylindrical or flattened stem-like bodies, which are often 

 more or less matted together, and which may cross one another in every 

 imaginable direction. From the filled-up burrows of ScoUthus (which 

 have actually been " burrows of habitation "), the burrows of Plan- 

 olites are readily distinguished by the fact, that though they often 

 pass obliquely to the bedding so as to penetrate several layers of the 

 rock, they are usually more or less nearly horizontal, and they are 

 never vertical except for a short distance at some abrupt bend in 

 their coui'se. 



The genus Planolites includes a large number of the supposed 

 vegetable fossils fron the Paheozoic Rocks which have been referred 

 to the genera Palceophycus and Chondrites. 



4. Planolites VULGARIS, Nicholson. {Ref. Proc.Roy. Soc. No. 144,, 

 1873). Fossil consisting of the casts of tortuous worm-tubes, which 

 are usually of an irregularly cylindrical form, sometimes thickened 

 in parts, and varying from a line to two or three lines in diameter.. 

 Sui'face smooth. 



Specimens referable to this widely diffused and variable species are 

 common in the Clinton Rocks. They agree doubtless with some of 

 the species of Palceophycus described by Hall and Billings fi-om the 

 Silurian Rocks of North America ; but they are undoubtedly casts of 

 the burrows of Annelides, and it seems better to abstain at present 

 from any attempt to found separate species upon the innumerable 

 varieties which they present. 



Locality and Formation.— ^XvlAotx Group, Dundas. . 



