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Cincinnati Society of Natural History. 



REMARKS ON SOME MARKINGS ON THE ROCKS OF 

 THE CINCINNATI GROUP, DESCRIBED UNDER 

 THE NAMES OF ORMATHICHNUS AND 

 WALCOTTIA. 



By Prof. Joseph F. James, 



Custodian Cincinnati Society of Natural History. 



The rocks forming the strata of the Cincinnati Group are full of 

 markings which have either been neglected entirely, or else have been 

 studied with erroneous ideas of their true nature. These markings are 

 most common at the horizons where the rocks contain tracks and burrows 

 which have been described as Fucoids. These have been shown* to be 

 mostly inorganic in their origin, and while some are deserving of names, 

 others are not. Other markings have also been described, sometimes from 

 imperfect specimens, sometimes with an imperfect knowledge of how they 

 were formed, or what they really represented. 



Among the markings which have received attention, there are a num- 

 ber of genera (five) and species (eight) which have been figured and de- 

 scribed in the Journal of the Cincinnati Society of Natural History, Vol. 

 II, pages 217 to 222, by S. A. Miller. The author of the paper considers 

 the species he describes to have been made on the "bed of an ocean hav- 

 ing no great depth, but where the water was almost motionless, part of the 

 time, and at others very slightly disturbed" (p. 217, 218). 



Such a condition of affairs may be considered as nearly impossible. 

 No ocean known is shallow and quiet at the same time, so quiet as not to 

 destroy marks which may have been made in very fine sediment. Some 

 of these markings, as described, are so delicate that the slightest move- 

 ment of the water would suffice to erase them ; and others are of such a 

 character that the movement of water is necessary for their production. 

 Instead, therefore, of regarding them as produced at the bottom of a shal- 

 low sea, it would be more reasonable to consider them as having been pro- 

 duced on exposed surfaces of mud, and in such proximity to the water 

 that deposits of mud would preserve them for future ages. 



One of these reputed tracks received the name of 



Ormathichnus, Miller. 

 The genus "consists of a single, continuous, beaded track or trail." 



* Journal Cincinnati Society of Natural History, Vol. VII, pp. 124, 151. 



