122 



The Canadian Field-Naturalist 



[Vol. XXXVI 



Considerable interest is attached to the finding 

 of two Desmostylus teeth in the Sooke formation, 

 both of which were collected in the cliffs between 

 Muir and Kirby creeks. The first one was found 

 in 1916, and is now in the B.C. Provincial Museum 

 at Victoria. It was determined by the late 

 LawTence M. Lambe, of the Canadian Geological 

 Survey, as the first right upper molar of the 

 Sirenian Desmostylus hesperus Marsh, of Pliocene 

 age.^ The tooth is considerably worn, and the 

 root is missing. It is composed of two longitudinal 



is larger and not so much worn. The length of 

 this tooth is 46 mm.; width: 34 mm.; diameter 

 of largest column: 24mm.; diameter of smallest 

 column: 17 mm.* The root of this tooth is also 

 missing, and the end column broken. The main 

 difference between these teeth and the American 

 and Japanese specimens is that each of the Sooke 

 teeth has a well developed cingulum. There can 

 be little doubt that these teeth represent an older 

 species than Desmostylus hesperus, as recent re- 

 search has shown that this formation is Oligocene 



A 



B 



Fig. la. 



Side and crown views of tooth of 



Desmostylus sookensis n. sp. 



Fig. lb. 



Side and crown views of tooth of 



Desmostylus sookensis n. sp. 



rows of appressed columns with a single column 

 at the posterior end. Each of these columns shows 

 the characteristic round pit in the centre. The 

 length of this tooth is 34 mm.; width: 24 mm.; 

 height of columns: 17mm.; diameter of largest 

 column: 15mm.; diameter of smallest column: 

 10mm. The second tooth was found in 1921 in a 

 large block of sandstone which had been dis- 

 lodged from the cliff and had fallen to the beach. 

 The number of columns and their arrangement is 

 the same as in the first tooth, but the second tooth 



in age, older than any of the formations in which 

 D. hesperus has been found. ^ The only other 

 species in the genus Desmostylus is D. watasei 

 Hay,'"' from Japan. ^ This species is represented 

 by one skull which was collected from sandstone 

 situated some distance above a Miocene deposit. 

 Taking into consideration the greater age of the 

 Sooke formation, and also the presence of cingula 

 on these teeth, they are, tentatively, named 

 Desmostylus sookensis n. sp. The specimen in 

 the B.C. Provincial Museum is the type specimen. 



