VINE : CARBONIFEROUS POLYZOA. 
331 
difficult to make out the typical characters of Glauconome found 
in the Shales. There are, however, marked fades in the species 
of this genus very easily recognizable even when many of the 
characters are absent. The Fenestella, and also the Paheocoryne 
of Duncan, are very well preserved. When species from either 
Gare or Belstonburn are compared with the species from the 
neighbourhood of Hurst and Richmond, there is a striking simi- 
larity between them ; so much so, that some of the more 
characteristic specimens from any one of the localities are scarce- 
ly distinguishable. This is especially true of the Fenestella 
polyporata, and the Palceocoryne radiatum, Duncan. At one time 
I was disposed to favour the idea that the Polyzoa of the York- 
shire, and the Polyzoa of Belstonburn districts, were of the same 
horizon ; and believing such to be the case, I wrote to Mr. John 
Young, of Glasgow, to that effect. In answer he wrote me : — 
" In your letter you say that the Polyzoa of the Richmond Lime- 
stone series resemble very much those from the Belstonburn 
Shale, Carluke. This latter Shale lies high in our upper Lime- 
stone series, not far from the millstone grit of our Scotch Coal 
Measures. It would be interesting to find what is the position of 
the Richmond series. Lately, I got some pieces of Shale sent me 
from Muirkirk, in Ayrshire, with fronds of Fenestella identical 
with those of the Belstonburn Shale. It also contains an un- 
described Potyzoa found in both localities."* 
This correspondence of specific type is not, however, com- 
plete. There is a difference in the abundance of species in the 
two places. In our Yorkshire Shales Rhabdomeson rhombiferum and 
R. gracile are very abundant. In the Belstonburn Shales these 
species are very rare. Sulcoretepora parallela, Phill., and Gonio* 
cladia cellulifera Etheridge. Jun., are about equally distributed ; 
and there is a similarity between the Polypora ; the Glauconome 
elegans, Young and Y., and G. aspera, Y.Y., present the same 
markedly crushed character ; but in the Belstonburn district we 
* Mr. John Young's Letter, dated May, 1878. 
