JReporfs and Proceedings — Geological Sociefg of London. 379 



ventral elements the centre of reference is the oral pole. Figure 13 

 is labelled Pisocriniis flagellifer, a name that is a synonym of 

 P. pilula. Fig. 14: is labelled Cijatliocrinns ramosus, just as all 

 text-book writers persist in labelling it, although in 1893 I proved 

 that the specimen belonged to C. longimanus. 



The descriptions of the species are clear, but comparison would 

 Lave been facilitated had the author been at the pains to construct 

 diagnoses ; while the labours of his successors might have been 

 lightened had he fixed on type-specimens for his new species and told 

 us in what collections such specimens were preserved. A few minor 

 points also need elucidation. Thus, the description of the arms in 

 Cyathocrinus cora does not seem to me to agree with Figs. 8 and 9 ; 

 since this is the most striking feature of the species, enlarged 

 drawings should have been given. The diagram of Ampherisiocriniis 

 on p. 67 seems to agree with the new species A. diibius rather than 

 ■with A. typus ; but this is misleading. The arms of the new species 

 Lampterocrinus dubius are said to differ from those of typical species 

 " in having no brachial plates of higher order than the costals," 

 or primibrachs ; but since the arms are not preserved, it is hard to 

 see how this can be proved. Archceocnnus has hitherto been 

 recognized only in the Trenton Limestone, but a species A. depresses 

 is here described, although the elevated median series of anals is 

 not characteristic of the genus. The new species described as 

 Platycrinus (?) dubius shows no sign of the large interradials usual 

 in that Carboniferous genus, and is more likely to be a Coccocrinus 

 or Cordylocrinus. Dr. Weller says that for most of his generic 

 descriptions he is largely indebted to the publications of others. 

 It is therefore not clear how much weight is to be attached to his 

 accounts of Gazacrinus, Stephanocriims, and Zophocrinus, all genera 

 about which fresh information was badly wanted. Dr. Weller's 

 own palceontological work has been quite enough to justify him in 

 publishing his own opinions and descriptions, and such a course 

 would more advance science and would fix the responsibility for 

 certain doubtful statements. 



Dr. Weller's further studies in the palaeontology of the Niagaran 

 Limestone of Chicago will be awaited with interest. They are 

 likely to fulfil the promise of this first one, and perhaps if the author 

 will take a friendly hint or two they will meet with an even more 

 favourable reception. F. A. Bather. 



S,E£^OJBT3 J^ISTJD :F>i^OGSE;IDII^^C3-S. 



GkOT.OGICAL iSoOTKTY OF LONDON. 



L— June 5th, 1901.— J. J. H. 'iVall. Esq.. M.A., V.P.R.S., President, 

 in the Chair. The following communicsations were read : — 



1. "On the Passage of a Seam of Coal into a Seam of Dolomite." 

 By Aubrey Strahan, Esq., M.A., F.G-S. 



The author was informed by Mr. N. R. Griffith in 1900 that the 

 Seven-Feet Seam of the Wirral Colliery had been found to pass into 



