R. Etheridge, jun.—Carboniferous Tubicolar Annelida. 215 
Diabase, from Penycil Promontory, a mass intrusive in Harlech 
Grits according to the Survey Map; the specimen sliced was taken 
from a little quarry near the 8. end, and has the appearance of being 
fresh ; it effervesces slightly with acid; it is dark sap-green in 
colour, with lustrous felspathic needles, pyrites, and minute segrega- 
tions of zeolite occasionally. 
Microscope.-—The long felspar prisms show banding, but have 
only a dull salmon colour when polarized; many are much decom- 
posed and permeated by viridite, or are corroded by areas showing 
zeolite and even calcite re-arrangements. The augite forms crystals 
of considerable size between the felspars, are without regular outlines, 
and have cracks, and their ordinary characters ; are pale yellow in the 
thin slice, and polarize brightly. Many, however, are visibly decom- 
posing, they pass into viridite; this is scattered about in flakes 
everywhere, and also forms tracts of larger size; it has under crossed 
Nicols a granulated appearance of dark indigo-grey, with in some 
places radiated fibrous circles showing the black cross ; some of these 
tracts are bordered by a botryoidal denser lining of granular viridite 
substance, within which is the fibrous radiating variety with aggre- 
gate polarization. 
Dendritic forms of black iron oxide with branches at right angles 
to the stem are present, besides crystals of ilmenite covered with 
opaque white oxide. BAB: TE. 
(To be continued.) 
I1V.—A Conrrisution TO THE Stupy oF THE British CARBONIFEROUS 
TuBicoLaAR ANNELIDA. 
By R. Erurrines, Jun., F.G.8., F.R.P.S. Edin. 
(Continued from p. 174.) 
Observations on Spirorbis.—In the foregoing history I have endea- 
voured to give a brief and clear outline of the views held by those 
who have made it the subject of their investigations since the time 
of W. Martin. 
Omitting this author, who undoubtedly looked upon it as a mollusc, 
we have first to consider the opinions of Murchison and Phillips, and 
there can be little doubt, I think, that, from the expressions made use 
of by these writers, they were quite conscious of the great affinity 
which Microconchus bore to the common Spirorbis, and hence to the 
Annelida. This is again apparent in the writings of Dr. Hibbert, 
although he called it a Nautilus; and when we take up Col. Port- 
lock’s work, we find the same form, with a similar habit, only under 
another name, and also a second species definitely referred to the 
genus Spirorbis. Following close upon these we have the researches 
of Dr. Dawson and Mr. E. W. Binney, rendering still clearer, if 
more evidence was needed, the Annelide,—or to put it in the very 
broadest sense possible, the Testaceous character of the organisms so 
clearly described by them. Under these circumstances it appears 
strange that such accomplished Palontologists as Messrs. Germar, 
Goéppert, Geinitz and others, should have been so ignorant of con- 
