Geological Society. 115 



the Crags, and four of them new to science. A remarkable low- 

 crowned, but broad, lower camassial tooth from the Norwich Crag of 

 Bramcrton is referred to the genua Lutra, and named specitioally 

 L. Eeevei. All the other specimens noticed below are from the 

 nodule-bed at the base of the ISutfolk Red Crag, and the first 

 four of them are in the possession of Mr. E. C. Moor, of Croat 

 Bealings. A right ramus of a lutrine lower jaw, differing from 

 the common Otter in having the hinder fangs of the premolars 

 much larger than the front ones, aud agreeing in this particular 

 with the Lutra dubiu of DeBlaiuville, is referred to the latter 

 species. X humerus of a Seal, most nearly resembling that of 

 Fhocu vitulina, but of smaller size aud more slender proportions, is 

 called Phocn Moori. Another Seal's humerus, having a peculiarly 

 triangular shaft, is thought to belong to the PhocaneUa minor of 

 Van Benedeu. A maxilla with three teeth, evidently belonging to 

 the genus Trogontherium, but of smaller size than the Troyontherium 

 Cuvieri, is believed to represent another species, and is named 

 T. minor. The ziphioid rostrum in the Ipswich Museum, which 

 received from the llev. H. Canham the MS. name of Mesoplodon 

 Floiveri, is for the first time described ; and another rostrum in the 

 Museum of Practical Geology, characterized by being very short 

 and with a deep boat-lilie anterior extremity, is named Mesoplodon 

 scaphoitfes. The peculiar species Aili(rus inirjlicus, hitherto known 

 only by a piece of a lower jaw with a camassial tooth, is now 

 further illustrated by a fine upper molar recently presented to the 

 Museum of Practical Geology. 



2. " On Burrows and Tracks of Invertebrate Animals in Palieozoic 

 Rocks, and other Markings.'' By Sir J. William Dawson, LL.D., 

 F.R.S., F.G.S. 



This paper, which is illustrated by photographs and drawings, 

 indicates some new facts in connexion with the markings pro- 

 duced by the burrows and tracks of animals and by other causes. 

 Kusichnites and Cruziana are regarded, like Climactichnites and 

 Protichuites, as representing probable burrows of Crustaceans and 

 Chsetopod worms. Scolithun canadensis is shown to be a cylindrical 

 burrow, with accumulations of earthy castings at its mouth. The 

 relation of these burrows to the forms known as Scotolithus, Astcro- 

 jjhj/cHs, Monocraferion, aud Astropolitlion is pointed out. 



Under the new generic name of Sahellarites the Author describes 

 certain tubes, composed of shelly and other fragments cemented by 

 organic matter, found in the Trenton Black-river Limestone. They 

 resemble the burrows or tubes formerly described by the Author 

 from the Hastings and Quebec Groups, and appear to be the tubes 

 of worms allied to the recent Sabell((ri(^ : but they are liable to be 

 mistaken for Alga? of the genera PalceopJiNcus and Buthotrephis. 



Some large cylindrical bodies from the Potsdam Sandstone are 

 described as having been supposed to be trunks of trees ; but the 

 Author regards them as probably concretions formed around slender 



