[MATTHEW] STUDIES ON CAMBRIAN FAUNAS 71 



Qize. — Height of the spire (which is somewhat crushed down) 13 

 mm. Height and width of the aperture each about 12 ram. 



Horizon and locality. — The sandstones of Kelly's Island in Concep- 

 tion Bay, which by Mr. Howley and Mr. Walcott are considered to be 

 Upper Cambrian. 



In general outline this species is not unlike B. lapicida, Salter, of the 

 Black Eiver hmestone.^ It is still more hke B. (P). Hortensia, Bill., and 

 B. (P). Harpya, Bill., of the Calciferous of western Newfoundland ^ ; it is 

 most like B. staminea, Hall, of the lower part of the Chazy in New York,' 

 but the last whorl enlarges more rapidly than in any of these species. 



Shaler and Foerste describe a minute gasteropod from lower Cam- 

 brian shale at Attleboro', Mass,^ which shows a general resemblance to 

 B, (?) Kelliensis, and the species cited above, but in its small size corres- 

 ponds to other spiral gasteropods of the Protolenus Zone. It has about 

 the same number of whorls as the Kelly's Island species and may be 

 collaterally ancestral to this type. 



ANNELIUA. 



AEENICOLITES, Salter. 



Arenicolites ANTiQUATUS, Bill. sp. (PI. lY., figs, la and b.) 

 Arthraria antiquata, Bill., Palœoz. Foss., vol. ii., pt. i., p. 66, fig. 33. 



This fossil, supposed by Billings to be part of a jointed plant, is 

 evidently the gallery which connects the paired burrows of a sea worm 

 of the genus Arenicolites. That author's description is as follows : — 



" Arthraria antiquata (n. gen. and sp.) The fossils for which the 

 above generic and specific names are proposed, are small cylindrical 

 bodies, with usually an expansion at each end, giving the form of a dumb- 

 bell. Those that I have seen are from six to nine lines in length, and, 

 from the manner in which they are grouped upon the surface of the 

 stone, they appear to me to be segments of a jointed plant. They exhibit 

 no internal structure, but the form is very constant Similar forms 

 occur in the Clinton formation." 



Arenicolites delighted in clear water and a clean sandy bottom ; in 

 which it built up the vertical holes which led to its burrow, as fast as the 

 sand accumulated on the bottom. When, however, the water was invaded 

 by muddy sediment it was in the habit of abandoning its old burrow and 

 forming a new one in the freshly deposited mud. Here as the sand 



1 Can. Organic Remains, Decade i., p. 12, pi. ii., figs. 1 to 3. 



2 Palaeozoic Fossils, vol. i., p. 227, fig. 211. 



3 Palaeontology of Nevir York, vol. i., p. 29, pi. 6, figs. 4 and 5. 



* Bull. Mus. Conap. Zoology, Cambridge, 1888, vol. xvi.. No. 2, p. 30, pi. ii., fig. 11. 



