138 not:es on the fossils of Ontario. 



times in the form of flattened impressions, differing in colour and 

 texture from the matrix in which they occur. That these enigma- 

 tical bodies branch, after a more or less regular fashion, is indiibit- 

 able, and it does not appear possible that they should have been 

 produced by Annelides or other marine animals. If they are plants, 

 however, their affinities are doubtful, and their mode of preservation 

 very obscure. 



Locality and Formation. — Clinton Group, Dundas and Hamilton. 



2. ScoLiTHUS VERTiCALis, Hall. (i?e/! Pal. K.Y. Vol. II., pi. iii, 

 fio-. 3.) This species is founded upon vertical circular tubes, some- 

 times slightly curved, which penetrate the strata more or less in a 

 perpendicular direction, and which open on the surfaces of the 

 laminae of deposition by regular rounded apertures. The average 

 diameter of the burrows is about one line, and then- vertical extent 

 is unknown. Often they are hollow ; at other times they are more 

 or less filled up with loose peroxide of iron ; or they may be com- 

 pletely filled up with sediment, when they present themselves as 

 smooth, rounded or cylindrical, vertical stems. That they are truly 

 Annelide burrows can hardly be doubted. They differ from ScolithuS' 

 linearis, Hall, in their smaller dimensions, and from S. Canadensis,- 

 Billino's, in not having an expanded aperture, and in apparently not 

 beino- curved towards their lower ends. The species is recorded by Hall 

 from the thick-bedded sandstones of the Medina Group, of Monroe' 

 County, State of New York ; but our examples are from ahigher horizon. 



Locality and Formation. — Clinton Group, Dundas. 



3. Arenicolites sparsiTs, Salter. {Ref. Quart. Journ. Geol. Soc. 

 Vol. xiii. p. 203). Paired burrows, with circular and comparatively 

 remote apertures, are not infrequent in the Clinton Group. They 

 vary considerably in size ; but they do not appear to be separable 

 from A. sparsus. of Salter, which commences in the Lower Cambrian 

 Rocks of the Longmynd, and is also not very rare in the Skiddaw 

 Slates of the North of England. The mouths of the burrows vary 

 from half a line to rather more than a line in diameter, and they are 

 usually placed about a line apart. 



Locality and Formation. — Clinton Group, Dundas. 



Genus PLANOLITES. (Nicholson).. 

 (Gr. pianos, a wanderer ; llthos, stone.) 



This name was formerly proposed by one of us (Nicholson, Contri- , 

 butions to the Study of the Errant Annelides of the Older Palseozoic 



