BV T. S. HALL. 655 



long as wide. Apertures at right angles to the axis'of the theca, 

 and slightly everted at their outer angle. The character of the 

 matrix does not allow the presence or absence of a spine to be 

 definitely asserted. 



The imperfection of the specimens in the sicular region prevents 

 their absolute identification, but they apparently belong to the 

 group typified by M. duhius, which ranges through almost the 

 whole of the Lower Ludlow and Wenlock in Britain. 



Loc. — Belle Vale, Yass. 



Horizon. — Lower Trilobite Bed, Bowning Series ( = Wenlock, 

 Upper Silurian). 



