Peculiar Fossils from the Chemung Rocks. 219 



questions which have been asked in regard to the biological rela- 

 tions of these singular "sandstone screws" from the Chemung. 

 The interior, in all cases yet observed, is composed of sand, Avith 

 sometimes small quartz pebbles. These indicate that the organic 

 tissue was soft, and early disappeared, leaving a cavity which was 

 filled m with sand and fine gravel introduced through an orifice 

 at one extremity. The upper end is conical and, in several speci- 

 mens which I possess, complete ; but the lower end is broken off, 

 and the nature o! the part removed remains unknown. It is 

 possible that we have nearly the entire organism, and that it was 

 fusiform with two conical extremities. This is, however, less 

 probable than that it continued below in some sort of a stem 

 that served as a support. Doubtless future discoveries will solve 

 this problem. 



The specimens in my possession may be concisely described as 

 follows : 



SP1RAXIS. (nov. gen.) 



Body cylindrical, or sub-fusiform, somewhat abruptly conical 

 above, more gradually tapering below ; surface traversed by two 

 parallel revolving spiral ridges, in some species closely approxi- 

 mated, in others separated by intervals half as wide as I he diame- 

 ter ; no traces of internal structure or distinct surface-markings 

 visible. 



Two species are known to me, viz., 



1. §piraxi§ major, n. sp. 



Pl. XVIII, Fig. 1. 



Bod}- cylindrical, about one inch in diameter, terminating above in a 

 conical summit, traversed by two strong spiral revolving ridges which cross 

 the axis at an angle of about 45°. These ridges are flattened or sulcated 

 and somewhat roughened, as though for the attachment of some frond-like 

 appendage. They are separated by broad, deep and smooth furrows about 

 three times the width of the flattened summit of the ridge ; the surface of 

 the furrow is smooth or obscurely granulated. 



Only a single specimen of this species is known, but this is remarkably 

 well preserved. It is about 7 inches in length by one in diameter. The 

 summit is complete, but it is broken off below, leaving the entire form un- 

 certain. It apparently shows a tendency to narrow downward, and the 

 spiral ridges are there somewhat more widely separated, as though tending 

 to open and become obsolete. 



Formation and localitv, Chemung Rocks, Southern New York. 



