36 



PROCEEDINGS OF WASHINGTON MEETING. 



given by Rogers (figure 6) differs somewhat in the annulated appearance from 

 those ordinarily given, hut it can scarcely lie anything else than Scolithus linearis. 

 It hears a striking resemblance to Planolites annularius, Walcott, as figured in a 



paper on the Olenellus fauna* That figure is 

 here reproduced (figure 7). The species occurs 

 in rocks of lower Cambrian age in Washington 

 county, New York. 



In L859 Murchison noted the occurrence of an- 

 nelid borings in the Stiper stones of England, f 

 referring them to Scolithus linearis of the Potsdam 

 M \ ^%JS sandstone of North America. The Stiper stones 



\\ ^ # ,t"*i« iMaPm are now considered to be of Lower Silurian age. 



. -™ ty ---■?• "' 



/ 



\ 



Figure 7 — Planolites annularius, Walcott. 



(After Walcott.) 



Figure 6 — Scolithus linearis, Halde 

 mann. (After Lesley.^) 



In 1861 Dr. J. S. Newberry in describing a sec- 

 tion at Diamond creek, Arizona, % referred to the 

 presence, in shales lying above and below a sand- 

 stone, of "great numbers of cylindrical bodies 

 which resemble the casts of worm-holes." These 

 are doubtless Scolithus burrows. The rocks over- 

 lying the beds with the worm-like bodies are 

 referred to the Potsdam upon lithological char- 

 acters and "their great relative antiquity." This 

 series is now known as the Tonto group, and is 

 placed in the upper Cambrian. 

 In 1861 Professor C. H. Hitchcock, in describing the Georgia group of Vermont, || 

 referred to Scolithus as follows: "The Scolithus linearis (Hall) is regarded by some 

 as a plant, by others as a relic of an articulate animal. It generally presents the 

 appearance of numerous linear stems, sometimes three feet long. The stems are 

 generally numerous, and much resemble a series of small pins driven into the rock. 

 Some authors have stated that the axis of this fossil is invariably at right angles 

 with the position of the strata. If so, it may be of great service where it occurs in 

 settling the position of the strata. It certainly would be in both of its localities in 

 Vermont." "Many have considered this fossil as characteristic of the Potsdam 

 sandstone. If this be so, then the age of the quartz rock is certainly known. It 

 certainly has never been described from any other rock ; hut we do not feel autlior- 



* Tenth Aim. Rept. U: S. Geol. Sur., pi. 60, fig. :.. 

 f Quart. Jour. Geol. Soc. London, vol. 15, 1859, \>. .'U.S. 

 % Rept. mi Colorado River of the West, explored under Iv< 

 I Dictionary of Fossils of Pa., vol. :;, 1890, p. 944. 

 Geology of Vermont, vol. l, 1861, pp. 356, :;.">7. 



in l857-'58, pari Ill, 1861, p. 5G. 



