232 
VINE : PALiEONTOLOGY OF THE WENLOCK SHALES. 
remains of the whole series, are situated nearly at the base of the 
Coalbrook Dale clays, and so far as certain life forms are concerned, 
are entirely cut off palseontologically, from the overlying rocks. 
Messrs. Davidson and Maw say, '* Below the fossiliferous Tickwood 
beds, from 1800 to 1900 feet of soft shales occur, which are compara- 
tively barren in organic remains, excepting only that at one-third 
from their base a remarkably rich zone occurs, the horizon of which 
seems to correspond closely with the Woolhope limestone of Here- 
fordshire, and possibly of the Barr limestone of Staffordshire, though 
in Shropshire the calcareous element is wanting. It is exposed on 
the east bank of the river Severn, a short distance above Buildwas 
Bridge, in a section including from 70 to 80 feet of shale beds. 
They are also exposed further to the west, by the side of the brook, 
south of Harley."'" 
The material from these beds, supplied to me by Mr. Maw, is 
more abundant, and comparatively speaking, much more important 
than from any of the other shales. The organic remains are innumer- 
able, and it was only when I began to pick out specific fragments for 
mounting that it was possible for me to speak satisfactorily of the 
life history of the various groups. The Crinoid slems are abundant 
in the No. 38 washing, and are largely encrusted with foreign objects. 
In July, 1881, soon after receiving the shales, I made a calculation of 
the number of organisms on 1000 Criuoid stems, picked out at ran- 
dom, 86 were encrusted by Monticuliporae, 80 by Stomatoporae and 
Ascodictyae, 7 by Ortonia, 27 with disk-like beginnings of various 
Monticulipora sp. , 24 root-like process or beginnings of young 
Crinoids, 228 pustulose specimeiis (borirgs by sponge?), and about 
550 fragments were comparatively tVee from eacrustations or borings. 
The organisms from the No. 36 washing are in some respects of 
a very specialised character, but my reasons for placing the collection 
after the Nos. 22 and 37 may be inferred from this. The Nos. 22 
and 37 washings, though poor in many other organisms, are literally 
crowded with fragments of Trilobita, and the Entomostraca are also 
of a very special character; Actinozoa are especially rare; restricted 
species of Polyzoa fairly abundant. 
* Op. Cit., p. 103. 
