402 D. A. MacAlister — Cassiterite and Specular Iron 



manifest that two of Owen's identifications are wrong. The two hones 

 internal to the nares which he regarded as nasals are the nasal 

 processes of the premaxillaries, and the two bones which form the 

 nasal floor and lie between the prevomers ('vomers') and the 



Fig. 2. Palatal aspect of skull of Tapinocephalus atherstoni, Owen : Karroo 

 formation, S. Africa (greatly reduced). 



maxillaries, and which were regarded as palatines by Owen, are 

 apparently septomaxillaries. This presence of septomaxillaries is 

 very interesting, as they appear to occur in Fareiasmirus and are 

 present in Therocephalians, Cynodonts, and Monotremes, but are 

 absent from Anomodonts. 



V. — Note on the Association of Cassiteeite and Specular Iron 



IN the Lodes of Dartmoor.^ 



By Donald A. MacAlister, Assoc. E.S.M., F.G.S. 



(with four text-figures.) 



SITUATED in the neighbourhood of Birch Tor, in the heart of the 

 granite mass of Dartmoor, at an elevation of between 1300 and 

 1400 feet, there are a number of tin-mines which have been worked 



1 Communicated by permission of the Director of the Geological Survey. 



