42 PROCEEDINGS OF WASHINGTON MEETING. 



Chickies quartzite of York county, Pennsylvania. He gave illustrations of the 

 tubes, flattened by pressure, and showed also an exposure of the quartzite with 

 great numbers of the tubes, often only | of an inch apart. No explanation is 

 given of their origin. This locality is tbe one from which the original specimens of 

 Haldemann came, and the form is doubtles the true Scolithus linearis. 



In the same year Brainerd and Seely, in a description of the Calciferous of the 

 Champlain valley* mention the occurrence of Scolithus minutus, Wing. This is 

 considered a burrow, and the authors say : 



"The fucoids, so far as we have seen, are not characteristic of any one division, though they 

 appear abundantly in various horizons of D. Further, Scolithus cannot be regarded as indicating a 

 Potsdam horizon, as the most abundant display we have ever seen i.- to be found at the bottom of 

 Division C, 600 or 700 feet above the Potsdam sandstone." 



In 1890 Professor J. P. Lesley referred f to and figured Scolithus canadensis and S. 

 linearis. Both were considered by him to represent worm burrows in rocks of Pots- 

 dam age. He also says: "But the old idea that Scolithus characterizes and deter- 

 mines the Potsdam sandstone must be abandoned" (page 943). He then refers to 

 the work of Brainerd and Seely, quoting their remarks on Scolithus burrows in the 

 Calciferous, and he also mentions numerous localities in Pennsylvania where S. 

 linearis occurs, referring the rocks to the Potsdam. He also says that similar worm 

 burrow casts occur in the outcrops of Medina sandstone. 



In 1890 C. T>. Walcott, in an account of the fauna of the lower Cambrian or 

 Olenellus zone,j states that Scolithus appears to range through the Cambrian. Bur- 

 rows in the Potsdam or upper Cambrian are similar to those in the lower Cam- 

 brian ; and though it is not considered probable that the same species of animal 

 made the burrows in the two epochs, there are no means of separating them. All 

 the Cambrian forms are referred to Scolithus linearis. 



In Bulletin No. 81 of the U. S. Geological Survey \ (just issued) Mr. Walcott gives 

 numerous references to Scolithus linearis and its occurrence in Cambrian strata. 

 From these it appears that numerous correlations of rocks from widely separated 

 localities have been made upon the evidence of this fossil. 



During the field season of 1889 I found at various points in Wisconsin and Min- 

 nesota specimens of Scolithus. At Madison, Wisconsin, for example, the tubes occur 

 in abundance, penetrating the rock in all directions. Near Ableman I found one 

 specimen having the shape of the letter U, both ends opening at the surface; 

 otherwise it was exactly like the ordinary specimens of Scolithus linearis. 



Near Merrillan, Wisconsin, on an isolated mound 11 miles southeast of the rail- 

 road station, an outcrop of sandstone occurs, part of which lias a columnar appear- 

 ance. When weathered, the columns stand out in relief and the top of the rock 

 has the appearance of a honeycomb with the cells sealed up. The same appear- 

 ance is presented by a sandstone 3 miles to the northward. These appearances are 

 probably due to Scolithus borings. 



From the review here given it is seen that, originally described as a marine fossil 

 plant by Haldemann, the annelidan character of Scolithus was first pointed out by 



♦Bull. Geol. Soc. Am., vol. 1, 1800, pp. 501-511. 



-(•Dictionary of fossils of Pennsylvania ; Second Geol. Sur. Penn., P4, 1890, pp. 913-945. 



| Tenth Ann. Rept., U. S. Geol. Sur., 1890, pp. 003, 604. 



I Correlation papers ; Cambrian : 1891, p. 447. 



