PLATE XI 
Fig. 18. Leveilleites hartnageli Foerste. From Credit Forks, Ontario. Both 
views are enlarged 10 diameters, arranged for use with a stereoscope. Same 
specimen as figure 18 on plate VI. This stereoscopic view is valuable chiefly for 
showing that the fronds consist of something more than a thin flat carbonaceous 
film. Some of the individual fibers can be recognized along the margin of the 
frond. 
Photographs by Prof. George H. Hudson. 
