J. F. JAMES — THE GENUS SCOLITHUS. 



41 



In 1884 Professor N. H. Winchell, in a description of the geology of Rice county, 

 Minnesota * noted in the St. Peter sandstone great numbers of circular holes. 

 They are always perpendic- 

 ular, and can be traced 2j 

 feet by furrows on the sur- 

 face of the rock. It was at 

 first ascribed to the burrow- 

 ing of Cretaceous mollusks, 

 "but," Professor Winchell 

 says, " it is more likely to be 

 due to some marine vegeta- 

 ble, or to worm-burrowing 

 of Cambrian age." "It would 

 be the same as if a multitude 

 of horse-tail rushes or others 

 were growing in the bottom 

 of the sea when the sand 

 was accumulating and be- 

 came gradually buried un- 

 der the sand, and then were 

 imprisoned and fossilized, 

 their presence only being 



Figure 14 — Eophyton (Scolithus) dispar, U. P. James (sp.). 

 (Original.) 



evinced now by the cementation of the sand grains about their extei-ior, or by a 

 looseness of the same in their interior." The spots were only seen on upper surfaces 

 of the rocks, and were from £ to J of an inch in diameter. 



This is also probably a species of Scolithus, possessing some of the characters of 

 linearis, some of woodi, some of delicatulus. Professor Winchell gave no name to the 

 form, but I propose to call it Scolithus minnesotensis. 

 It is probably this same form that occurs at Beloit 

 and other places in Wisconsin. 



In 1887 Ami referred f to the existence of Sco- 

 lithus in Chazy strata, stating that although Scolithus 

 had been considered to indicate the rocks contain- 

 ing it were Potsdam, its occurrence at other hori- 

 zons shows the beds may be of a later age. 



In the same year Messieurs Ami and Sowtercon- 

 cluded,J as a result of the examination of an exten- 

 sive scries of specimens from the Potsdam of the 

 province of Quebec, that S. linearis and S. cana- 

 densis were identical. The main difference between 

 the two, they concluded, was in the preservation, 

 the former occurring as casts of the burrows or 

 holes, while the latter were the burrows them- 

 selves. 



In L890 Atreus Wanner referred? to Scolithus K| ,, IUK ,.-, Scolithus delicatulus, V. 

 occurring in great abundance in the Hellam or P. James. (Origin 





\ l Bx u 



♦ Geology oi Minnesota; Final Report, vol. 1, 1884, pp. 656, 657. 

 fCanadian Bee. Bci., vol. ii, 1887, pp. 304-306. 

 | Ottawa Naturalist, vol. i, 1887, pp. 96, 97. 

 \ American Geologist, vol. \ . L890, pp. 35-38. 



Gkol. Boc. Am., \ "i. 3, i-'i 



