36 PROCEEDINGS OF THE ACADEMY OF [Part I 



Mycetopoda diluculi n. sp. Plate III, fig. 1. 



The single example is imbedded in reddish shale, showing part 

 of one side and a section, from presumably near the anterior end, 

 which is broken away. 



The shell is quite compressed, apparently rather thin, of long, 

 narrow^ straight form. The surface shows distinct wrinkles of 

 growth, which by their outlines indicate a rather strongly tapering 

 posterior end. 



The length of the part preserved is 99 mm. Alt. at broken end 

 30 mm. ; further back, where the ventral margin is visible, the alt. 

 is about 25 mm. Diam. at broken end 9.5 mm. 



Mycetopoda is a recent genus of South America, with a few species 

 as far north as Nicaragua and Guatemala. While the generic refer- 

 ence of the fossil is not positive, the interior being unknown, its 

 characters, so far as they are legible, agree well with Mycetopoda, 

 and appear to indicate this genus or one closely similar. 



Locality: Shale, Little Conewago Creek (loc. 5). 



POLYCHAETA. 



Spirorbis inexpectatus n. sp. Plate III, fig. 3. 



In the "red" (deep brownish drab) shale there are small, spiral 

 bodies resembling the tubes of Spirorbis. They occur in groups 

 scattered on surfaces of uncertain nature, or sometimes shells. They 

 occur about half immersed in the matrix, or somewhat deeper. 



The spiral is in one plane. The largest individuals measure 

 2 mm. About one and a half turns seem to be present, but only 

 the last is clearly seen. This increases in width rather slowly, 

 always in clockwise direction. The surface of the spiral shows 

 sculpture of weak, retractively radial folds on the lateral convexity, 

 and there are also fine striae in the same direction. The tube appears 

 to be oval in section, its periphery rounded. 



From the uniform direction of coil it appears that the same side 

 is always exposed, the under side probably being attached. 



Locahty: Shale, Little Conewago Creek (loc. 5). 



Feeling some uncertainty about these fossils a specimen was 

 submitted to Dr. John M. Clarke, who reported as follows: 



"I think there is little doubt that the specimen you have sent 

 to me is Spirorbis. These tube-secreting worms show themselves 

 to have been highly adaptable throughout Mesozoic and Paleozoic 

 history. In the Carboniferous their tubes cover the leaves of coal 

 plants and they are not unknown to us attached to terrestrial water- 

 carried plants of the Devonian. 



"This specimen before me carries the impression of a leaf or the 

 interior of some thin-shelled mollusk which might well have been 



