600 



SIR J. W. DAWSON ON BrRROWS AND TRACKS OF 



Fig. 4. — Climacticlinites and ProticJinites, associated on the same 

 slab. From the Potsdam Sandstone of Ontario (in the Peter- 

 Redpath Museum). About -^t^ of natural size. The large slab 

 is the overlying impression ; the small one, placed below, is the 

 underlying surface. (From a Photograph.) 



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