298 Prof. T. G. Bonney— Welsh Pre-Cambrian Rocks. 
Our Yorkshire species is evidently near to Natica calypso, D’Orb. 
(T. J. vol. ii. p. 202, Atlas, pl. 292, figs. 9 and 10), which is common 
in the Oxfordian of Neuvisi in the Ardennes. D’Orbigny observes 
that at first sight his species has more resemblance to a ‘‘ Phasianella” 
than to a Natica, but as he had already described a somewhat similar 
form which is undoubtedly a Natica, he concludes to place the 
species named Calypso in this genus. 
Casts and imperfectly preserved shells of Natica arguta occur 
sparingly in the Corallian of Yorkshire, but the precise locality 
where they have been found is unknown to me. 
Natica cincta, Phillips.—No shell answering to this figure (Geol. of Yorks. pl. iv. 
fig. 9) has ever been observed by me in any collection trom the Corallian beds. I 
once saw the original specimen under glass at the Leeds Museum, and it impressed 
me as being more like WNatica Leckhamptonensis, which has been found in some 
Inferior Oolite Limestone near Castle Howard Park. Professor Morris had also 
arrived at a similar conclusion. 
EXPLANATION OF PLATE VIII. 
Fic. 1. Purpuroidea nodulata, Y. and B. Coral Rag of Langton Wold. Back 
view. York Museum. 
were be $5 Another specimen. Coral Rag of Langton Wold. 
Front view. York Museum. 
a3 ick ae $5 Another variety, with different style of ornaments. 
Coral Rag of North Grimston. Back view. My 
Collection. 
» of. andd. cf. tuberosa, Sow. Coral rag of Langton Wold. Back and 
front view. Leckenby collection. 
EXPLANATION OF PLATE IX. 
Fic.'1a. and 14. Natica buccinoidea, Y. and B. Coral Rag of North Grimston. 
Front and back views. My Collection. 
yy) 2a. and 20: a elymenia, D’Orb., probably from the Coral Rag of 
Langton or Grimston. Front and back views. 
Strickland Collection. 
BE ie clytia, D'Orb. Coral Rag of Settrington railway 
cutting. Front view. My Collection. 
parle x As arguta, Phil. Corallian of Yorkshire. Front 
view. York Museum. 
>, oa. and b. 23 ne Larger type. Corallian of Slingsby. Front and 
back views. Leckenby Collection. 
(To be continued.) 
IJ.—On Some Recent Cuassirications oF WerLsH Pre-CAMBRIAN 
Rocks. 
By Pror. T. G. Bonney, M.A., F.R.S., F.G.S. 
WO papers, presented by Prof. Hughes to the Geological Society 
during the last twelve months,! call for some comment from 
myself, as in many respects they controvert, directly or indirectly, 
opinions which I have expressed before the same Society.” In the 
debates which followed I objected to the imperfect evidence on which 
these criticisms were founded ; and as the author repudiated with 
some warmth my right to demand that conclusions founded not only 
on field work, but also on microscopic study, should not be assailed 
from the former point of view alone, I will venture to state the 
* Read May 14, 1879, and Feb. 25, 1880. 
* Quart. Journ. Geol. Soc. vol. xxxv. pp. 309, 321. ‘ 
