108 F, R. Cowper Reed—Girvan Crustacea, ete. 
. The Yarra concretions being formed as they are of clayey masses 
Surrounding fragments of plants are, however, directly comparable 
awith the clay concretions and clay ironstones which are constantly 
found in the English Coal-measure beds, and which have also yielded 
many valuable specimens of fossil vegetables. These, however, are in 
no way comparable with the true ‘ coal-balls , which are a formation 
as unique and as characteristic as any str ucture in the range of geology. 
_| That it is ‘‘ worth a further enquiry ”’ into the theories of formation 
of the English coal-balls, is a conclusion with which one can heartily 
agree with Mr. Chapman, even while controverting his original premises, 
-and I may add that during the last few years, “assisted by the Royal 
Society and in conjunction with Mr. Watson, I have been undertaking 
-work of an extensive and detailed nature on the subject. The results 
of this work all point to the truth of the zm sctd theory for the coals in 
which the true ‘coal-balls’ are found, and in a full paper we hope to 
Set forth the many and various facts which support this statement, 
At must not be forgotten, however, that the coals in which these 
Structures occur are in many ways rather special cases, and show 
certain characters which are almost unique, so that ‘‘the evidence 
already known, which goes to prove an allochthonous origin for much 
of the coal- deposits of various ages in different parts of the world,”’ 
does not affect the question. Geology i is now sufficiently advanced to 
‘recognise that there may be two or more modes of formation for the 
“various coal-seams. ‘When structures so characteristic and so unique 
.as the true calcareous ‘coal-balls’ occur in a seam, it is but natural 
to be prepared to find that some rather unusual conditions were 
associated with the deposition of that coal. 
To conclude. It appears that in the facts of importance in their 
structure and origin the Yarra nodules do not resemble the calcareous 
nodules known as ‘ coal-balls,’ and that therefore conclusions as to the 
‘origin and occurrence of the latter based on a comparison with the 
former must inevitably be fallacious. The Yarra concretions are none 
the less interesting, and may be compared with other concretionary 
structures in the Carboniferous with great advantage. 
IV.— Srpewick Museum Norss. 
eh CRUSTACEA, ETC., FROM GIRVAN. 
By F. R. Cowrrr Resp, M.A., F.G.S. 
-(PLATE IY.) 
{|\HE numerous and full accounts of the Crustacea (apart from 
trilobites) from the Girvan area which Professor Rupert Jones, 
Dr. H. Woodward, Mr. R. Etheridge, jun., and others’ have published 
‘during the last three or four decades may seem to render any further 
remarks by me superfluous. But at Dr. Henry Woodward’s suggestion 
Mrs. Gray recently sent to me some fresh material for examination, 
which, in addition to yielding some new species, throws some interesting 
1 Peach: Proc. Roy. Phys. Soc. Edinburgh, vol. xiv (1902), Session 1900-1901, 
Pres. Add., p. 369. 
