FEOM OSMINQTON MILLS, DOESET. 



By Professor J. BUCKMAN, F.L.S., F.G.S., Ac. 



I HE genus Trigonia of Bruguiere, Lyriodon, of Goldfuss, 

 is represented by some three forms of species or 

 9] varieties, now found on the Australian shores ; while 

 over 100 species occur in the fossil state. 



Our present remarks apply to a form which, from its being 

 armed with raised tubercles, is placed in the division of the 

 Clavellata and our species is called Trigonia clavellata and is 

 typical of this division. One of the best drawings of this 

 species is by Sowerby, Min. Conch., pi. 87, in reference to which 

 we have the following remark: "I have figured this from a 

 specimen sent me by the Eev. S. Eackett, from Eadipole, near 

 Weymouth, such is also found at Portland. The shell is pre- 

 served of much the same texture as a recent oyster shell which 

 has laid in a blackening mud." (Min. Conch., vol i., p. 197). 

 This fixes the locality and geological position, and is interesting 

 as showing that certain clavellated forms from the inferior oolites 

 should not be confounded with the species clavellata, though 

 placed in the group of which it is the type. 



The formation whence these specimens are derived is that, 

 perhaps, determined by Messrs. Blake Hudleston to be a 



