40 



PROCEEDINGS OF WASHINGTON MEETING. 



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In a later publication * Professor Whitfield referred this form to the genus 

 Arenicolites, considering that while there might he some doubt as to the animal 



origin of S. linearis of New York, 

 there was no question about the an- 

 imal origin of the Wisconsin form. 



In 1881 Nathorst f referred to the 

 occurrence of Scolithus in northern 

 ( HTiiiany, and he notes that Dames 

 expressed some doubt, in which he 

 himself shared, as to the organic 

 origin of the species. This doubt 

 arose from the fact that the tubes 

 were always parallel and never 

 transverse. Some specimens, how- 

 ever, he considered were undoubt- 

 edly worm tubes. 



In 1881 Mr. U. P. James J men- 

 tioned a species referred to by him 

 as perhaps Scolithus linearis occur- 

 ring in the Cincinnati group of Ohio. 

 It is found on the under side of slabs 

 of limestone, and is described as fol- 

 lows: 



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Figure 13 — Scolithus woodi (sp.). (After Whitfield.) 

 View of surface ..1 slab. 



" The fossils are shown in strong, raised 

 lines, from 1-21 to over }4 inch or more 

 wide, generally straight and parallel to 

 each other, but not always so." 



Should the species prove to be distinct from S. linearis it was proposed to call it 

 S. dispar. This form is not a Scolithus in any sense of the word, but is probably a 

 species of Eophyton. The lines were produced by the passage of some organism 

 over the surface of soft mud (figure 14). 



On the same page of the above publication a second species is described under 

 the name of Scolithus delicatulus (figure 15) : 



" It consists of small, cylindrical stems, from half a line to one line in diameter, passing vertically 

 through the strata, irregularly arranged from % to % of an inch apart, mure or less. The appear- 

 ance is as if soft mud, forming the strata, had 1 n deposited gently around the plants without dis- 

 turbing their erect position. * * * < >n the under side the plants are broken off even with the 

 surface, or leaving small, shallow pits; oil the upper surface they arc elevated from half a line to 

 over one line."g 



As we see, this form was considered a plant, but there can be no question about 

 its being a worm burrow. 



In 1883 Professor T. C. Chamberlin|| figured Scolithus (?) woodi, Whitfield, as 

 Arenicolites woodi, saying he preferred this name, as the annelidan character of the 

 fossil had been determined. 



* Ibid, p. 177. 



fOn traces of some invertebrate animals and their paleontological significance (in Swedish and 

 French) : Stockholm, 1881. 

 X The Paleontologist, No. 5, June 10, 1881, p. 33. 

 I Ibid., pp. 33, 34. 

 || Geology of Wisconsin, vol. 1, 1883, p. 128. 



