c G.' W. Lee — Trepostomata. 
155 
limestone (M. 273) from the Birkwood burn, Lesmahago, Lanarkshire, contains numerous 
•examples of a Stenopora agreeing in its main features with Stenopora redesdalensis , but 
differing from it in having much smaller acanthopores, the zoarium being also smaller. 
The bed it comes from is either in the upper portion of the Calciferous Sandstone or at 
the base of the (Scottish) Lower Limestones,' that is, at the top of the Visean. 
Observations. —The name redesdalensis is given here to the species which Nicholson 
■described as Monticulipora ( Beterotrypa) tumida Phill., and the description is based 
principally on Nicholson’s own materials, represented by some 500 specimens preserved 
in the Geological Department of Aberdeen University. A new name was called for, 
since, the type specimen of Phillips’ “ Calamopora tumida ” being lost, the attribution 
•of any form to that species is not permissible, owing to our entire ignorance of its 
taxonomic position. 
It will be seen that there are some discrepancies between the above description 
and that of Nicholson, who states that the walls do not exhibit the moniliform 
structure, and that tabular are present in the peripheral region. The first statement 
depends possibly on a question of individual appreciation, Nicholson having probably 
■estimated that the rather weak beading of the walls in this species was not to be 
compared with the distinct beading obtaining in other species, in which it is a more 
striking feature. As regards the second statement, it ought to have been qualified : 
when tabulae are present in the peripheral region, they are restricted to its inner 
portion. Moreover, the examination of two slides in the Nicholson collection—which 
agree very well with the longitudinal section, fig. le, loc. cit. —suggests that the 
features delineated as tabulas in the outer portion of the peripheral region of the 
specimen represented in the above quoted figure, are probably not tabulse but zones 
of dense sclerenchyma. 
It is hardly necessary to add that the Redesdale species is, according to the 
modern views, neither a Monticulipora nor a Heterotrupa. As regards its attribution 
to the genus Stenopora , it must be understood that it is made under the reservation 
•expressed in the concluding portion of the notes on that genus (p. 149). 
The specimen from which the section figured, plate xv, figs. 1, 2, was prepared, 
belonged to materials kindly lent by Dr. A. Vaughan and had been collected by 
Mr. S. Smith from the Redesdale Ironstone Shale. 
