64 Woodwardian Museum Notes— 
tion. Microscopically they are compact very hard argillites much 
jointed, with a flinty fracture. The more northern of the two 
~ masses exhibits the more distinct signs of bedding. Under the micro- 
scope the ground-mass appears dull, greenish, or greenish-brown, 
enclosing clearer generally crystal-shaped areas, which apparently 
indicate an incipient formation of andalusite. Very minute high- 
polarizing microliths of a fibrous character are scattered through the 
slide. Occasionally definite grains of quartz or felspar are preserved, 
which were doubtless constituents of the original sediment. In 
the southern specimen they are more numerous in one part, which 
therefore must have been very slightly coarser in texture. ‘The two 
specimens do not exhibit any important differences, but in the more 
northern the incipient crystals perhaps contrast more sharply with 
the ground-mass. This consists of granules or quartz possibly felspar, 
with opacite, and abundant minute flakes of a brownish to a greenish 
mineral. The former variety (which dominates in the more northern 
outcrop) is almost certainly biotite; the latter (which characterizes 
the other rock) is more like a chlor ite, but it may be only a hydrous 
form of the same mineral. 
The “chloritoschiste” of M. Noury at Petit Part was also ex- 
amined.! He describes it as “‘d’une schistosité encore marquée 
malgré le contact des porphyres pétrosiliceux,” but this structure 
did not appear to Professor Bonney remarkable, so far as he saw 
the rock. M. Noury also speaks of it as the last member of the 
“terrain primitif” of the globe, so a specimen was brought away for 
examination. In the field it had the aspect of an ancient rather 
basic igneous rock. Under the microscope it exhibits idiomorphic 
felspars much altered, some certainly plagioclase, some perhaps more 
nearly resembling orthoclase, with other porphyritic crystals which 
are very possibly pyroxenic, and are replaced by a carbonate such 
as ankerite or dolomite, sometimes with associated pyrite. The 
matrix consists of felspar much kaolinised, of viridite, of a carbonate 
which may have formed as a pseudomorph in felspar, and of crowded 
specks of pyrite. The specific gravity is 2-74. The rock is therefore 
a rather basic porphyrite. 
V.—Woopwarpian Museum Notes. 
By F. R. Cowrzr Rezp, B.A., F.G.S. 
N the Burrow Collection of fossils from the Carboniferous Lime- 
stone of the neighbourhood of Settle I have recently found 
a form of the genus Oyclus which seems to deserve notice. From a 
careful comparison with the figures and description of C. Harknesst 
(Woodw.) in Dr. Woodward’s Monograph on Fossil Crustacea, to 
which we owe the greater part of our knowledge of the genus, I 
should consider it to be a new form allied to that species. 
It may be described as follows (using Dr. Woodward’s terminology) : 
buckler oval; length 44 lines; breadth 32 lines; greatest height 
23 lines; surface granulated. In profile the buckler appears hemi- 
1 Géologie de Jersey, pp. 53, 126. 
