J. F. JAMES THE GENUS SCOLITHUS. 



39 



Figure 11 — Scolithus (?) tubero* 

 sms, Miller and Dyer. (After Miller 

 and Dyer.) 



Figure 11 is reproduced from the figure given by the authors. The description 

 does not agree with the generic description of Scolithus, and it is evidently not con- 

 generic with S. linearis. It should be referred to a 

 separate, probably a new, genus. 



In 1878 Dr. T. S. Hunt, in a special report on the 

 trap dikes and Azoic rocks of Pennsylvania,* gave a 

 short history of Scolithus. He referred to the descrip- 

 tions of Haldemann, Hall and Eogers, and quoted the 

 description of Billings and his remarks relative to S. 

 canadensis. lie said that examples of Scolithus from 

 the Potsdam of Wisconsin appear to be identical with 

 S. canadensis, and, although probably distinct, are 

 more like S. verHcalis from the Medina than S. linearis 

 from the Primal of Pennsylvania. He says further : 

 "It would appear that even in the typical Potsdam 

 sandstone there have been confounded under this 

 name the marks of distinct and unlike objects." f 

 Some beds at Port Henry, New York, contain im- 

 pressions which have been designated Scolithus. These 

 are described as cylindrical cavities with a central tube. In weathered specimens, 

 where this central tube has disappeared, the cavities resemble the burrows of a 

 worm. " But," he says, "in either condition they are evidently very distinct, both 

 from the prismatic shapes noticed by Billings under the name of Scolithus canadensis 

 and the transversely grooved cylindrical rods of the Primal white sandstone." J 



In 1880 Professor R. P. Whitfield described a form from the P< itsdam of Wisconsin 

 which he called Scolithus (?) woodi. t 

 It consists of vertical and usually cylin- 

 drical perforations, about a line or a 

 little more in diameter, and from 1 to 

 several inches in length. They arc 

 straight or variously bent, lint never 

 bifurcating or branching. The walls 

 are usually smooth, but occasionally 

 one is corrugated (figure 12). In his 

 comparisons with other forms it was 

 said that while X linearis is from ,1 to 

 ■' inch thick, and often several feet in 

 length, the western forms are seldom 

 even jl, and often /„ of an inch in 

 diameter. Though normally vertical, 

 they are frequently deflected at vari- 

 ous angles or even run obliquely. On 

 some blocks many little elevations ap- 





Fiodbe 12— Scolithus in, mii t Whitfield («p 



ll'A///;. /</. > Sectional view. 



pear about the mouths of the burrows, and the surface is covered with trails of 

 annelids I figure L3). 



♦ Second Geol. Sur. Penn., E, L878, pp. L33 139 

 ! Ibid., p. L38. 



! /'■>./., p. 130. 



gAnn. Etept. Wise. Geol. Sur. for 1877, 1880, i>. iv 

 i •• ologj of w i consin, vol. iv, 1882, pi. 2, •< I 



