w. 
CARBONIFEROUS CORALS AND BRACHIOPODS 131 
leatus, Martin, and to Productus muricatus, PhilL, but is 
quite distinct from either ; since, however, its characters 
cannot be completely defined entirely from the specimens 
in the collection, I defer a detailed description to a more 
fitting place, where I can include the large number of speci- 
mens I have myself collected, with the express purpose of 
completely defining this very interesting form. 
The few specimens in the collection are derived from 
the “ Lower Limestone Shales.” 
Productus martini, Sow. 
A single specimen containing a group of examples (cf. 
PL 43, fig. 7. Dav.) represents this very characteristic 
form in the collection. 
Productus degans, McCoy, is represented by a single 
specimen. 
Productus semi-reticulatus, Martin, is represented by a 
very few indifferent examples. 
Productus {Marginifera) longispinus (?), Sow. 
This species, which has given its name to a particular 
horizon in the lower part of the Great Quarry, is only re- 
presented in the collection by a small piece of shale which 
exhibits a few long spines scattered over its surface. I 
consequently defer for the present the inquiry as to the 
relationship which the form found at Bristol bears to the 
more normal type found elsewhere. 
Productus aff. Cora, d’Orb. PL II. fig. 4. 
I here figure a specimen of the form usually accepted as 
representing Productus Cora, in order to illustrate the 
nature of the ribbing and the type of cross wrinkling. The- 
specimen agrees very well with specimens in the Davidson 
collection which are included under this species. 
The most noticeable features are the two distinct zones 
L 
