PROCEEDINGS, 1<S71 — 1877. 
367 
possible with which formerly we were unable to cope. Perhaps few 
better examples could be named than the subjects of the present 
communication. The four groups of crinoids herein described all 
agree in the number and general arrangement of the plates which 
form the calyx or body cup. In other words, the numerical elements 
of the essential portions of their generic formulae are identical. The 
special proportions of these plates, however and the general charac- 
ters of the crinoids differ in each, and when the whole sum of the 
resemblances and differences of genus with genus is compared, and 
when the types are examined in their entirety few will dispute the 
propriety of establishing the groups as above indicated. 
Mr. G. H. Parke drew attention to the discovery of a mineral 
new to Britain, called vermiculite, which had been found in the 
boulder-clay of Walney Island. The mineral occurs in both red 
and grey granite, taking the place of mica, with quartz and felspar. 
Examples were exhibited which varied in size from l-32nd to o-32nd 
of an inch. Being carefully detached from the matrix and placed on 
a platinum dish exposed to the flame of a spirit lamp, the water held 
in combination was driven off, and each piece of mineral exfoliated, 
lengthened, and twisted about like a worm, attaining a length of 
about I of an inch. The author suggested that the name vermiculite 
granite should be applied to the rocks which contained this mineral. 
An introductory paper on the structure, habits, and distribu- 
tion, together with the classification of existing Cephalopoda, was 
communicated by Mr. W. Cash ; his intention being to describe 
in future papers the fossil examples of this group existing in the 
strata of Yorkshire. 
Mr. James W. Davis read a paper on the unconformability of 
the Permian Limestone to the Red Rocks west of its escarpment in 
Central Yorkshire, in which, after describing the character of the 
carboniferous rocks to the westwards and the Permian beds eastwards 
of its escarpment, he drew the conclusion that the red grits and 
shales occurring immediately beneath the limestone at Scriven, 
Knaresbro', in the St. Helen's Quarry at Newsome Bridge, and other 
places, were rocks of a carboniferous age, the colours of which 
had been changed by the oxidation of iron due to the permeation of 
