26 The Ottawa Naturalist. [April 



belongs. It is the occurrence of this example towards the north 

 of the region that inckices the belief that the geological horizon 

 is there lower than farther to the southward. 



Locality. — Limestone Rapids, Fawn Branch, Severn River, 

 A. P. Low,' 1886. 



Another specimen presents an epitheca comparable with 

 that of C. vesiculosum and also shows a faint evidence of the 

 typical structure. Its identification is, however very question- 

 able. 



Locality. — Little Current River, 3 7 miles from mouth, 

 W. J. Wilson, July, 1903. 



Clathrodictyon drummondense. Parks. 



This species occurs on Drummond and Manitoulin Islands 

 and at Louisville, Ky. A full description may be found in the 

 above-mentioned University of Toronto Study. Briefly it is 

 characterized by a coarser structure than C. vesiculosum, and 

 like that species it is capable of considerable variation in the 

 crumpling of its laminae. The present example differs from 

 the type in a more marked crum.pling and consequent irregu- 

 larity, and in the fact that this appearance is presented in bands 

 corresponding, no doubt, to seasons of growth. If the laminae 

 of this species are bent into "chevron-like folds" it passes into 

 C. jastigiatum and there is no doubt that a close relationship 

 exists between the two. 



Locality. — Rainv Island, Attawapiskat River, Robert^Bell, 

 1886. (See Pal. Fos^. Vol. Ill, Pt. IV, p. 244). 



Clathrodictyon fastigiatum, Nich. 



A fragment, in all probability referable to this species, is 

 found in association with Actinostroma tenuifilatuni and Stro- 

 ■matopora carteri. The minute structure is largely indeterminate, 

 but the vesicular character of the interspaces and the folding 

 of the lan'iinae are faintly perceptible. 



Locality. — Station 641, Pagwachuan River, W. J. Wilson, 

 July, 1904. 



Clathrodictyon variolare, von Rosen. 



A very small fragment is referred to this species. As its 

 vertical extent is only a couple of millimetres, it is manifestly 

 impossible to see the rov/s of large v^esicles which alone dis- 

 tinguish the species from C. vesiculosum. It is, however, possible 

 to make out the character of the fibre, and this, taken in connec- 

 tion with the mammillated surface, renders the above identifica- 

 tion highly probable. 



Locality. — Equan River, D. B. Dowling. 



