1909.] NATURAL SCIENCES OF PHILADELPHIA. 297 



earlier it had been correctly given as a worm-burrow in Dana's Manual, 

 where it was said to be common in the Potsdam sandstone. Walcott 

 later found it to be Cambrian; and said, in 1890, he had never seen it 

 in the classical Potsdam. 



Specimens were met with during a field excursion of the Minera- 

 logical and Geological Section on October 17, 1908, which fully 

 demonstrated with remarkable clearness that the Scolithus linearis is a 

 worm-burrow in the sand of a sea-beach. In one of Mr. Bean's Cam- 

 brian quartzite quarries, called by him the Davis quarry, at the eastern 

 end of the North Valley Hill and at three-quarters of a mile southwest 

 of Valley Forge, many burrows of Scolithus linearis were found ; 

 and on one small slab, with burrows, numerous little circular ridges were 

 instantly recognized by Mr. F. J. Keeley as the crater-shaped orifices of 

 Scolithus holes precisely like those of sand-burrowing worms to be seen 

 on our present sea-beaches at Atlantic City and elsewhere (Plate X). 



The highly interesting and useful, perhaps hitherto unique slab, 

 5J X 6J inches, was presented to the Academy by the finder, Mr. 

 Alan G. Smith. It is well, however, to bear in mind, that further 

 quarrying may, of course, disclose other equally perfect specimens 

 that originated on the same ancient sea-beach. 



A somewhat similar burrow with a rather complete orifice was found 

 by the late Ellis Clark "in the Siluro-Cambrian limestone of Lehigh 

 County, about a quarter of a mile north of Helf rich's Spring:" and is 

 described by Prof. Frederick Prime in Report D2, p. 79, of the State 

 Geological Survey, 1878. The fossil was submitted to Dr. Otto 

 Torell, Director of the Geological Survey of Sweden, and at once 

 recognized by him as belonging to his genus Monocraterion, and given 

 the specific name of lesleyi. The genus is closely allied to Scolithus, 

 but the straight tube "gradually expands at the top into a funnel- 

 shaped cavity, corresponding to a like protuberance in the animal." 

 The smaller part of the tube is larger than our Scolithus; and in one 

 specimen is three-eighths of an inch in diameter, with the funnel ex- 

 panding, within a length of half an inch, to an inch or more in diameter. 



The following were ordered to be published : 



