part 2] ACL/.'ijjS\4 a^d aclisoides. 63 



the late Dr. Arthur Yaughan's zones can onl}'' be regarded as 

 temporary and approximate. 



Prof. E. J. Garwood has very kindly given me his views, based 

 on the information at present available. He considers the Lower 

 Limestone Series to be homotaxial with D^-D^, and the Upper 

 Limestone Series with Dy-? Dg. The Settle Limestone is S2 

 and D,. Widdale Fell, Mosedale, is Dy. 



The Upper Limestone of Poolvash (Isle of Man) is probably 

 D^-D.,. Mr. J. Smith's gasteropoda came from the partly dolo- 

 mitized upper limestone east of the Balladoole Fault, Poolvash. 

 He believes the horizon to be lower than that of the Hurlet 

 Limestone of the West of Scotland. 



With regard to the Irish localities, Cullion, DraperstoAvn, and 

 Carrickoughter. Kesh, Prof. Gr. A. J. Cole states that the districts 

 require careful zoning before the exact positions can be ascertained. 

 Dr. Yaughan considered that the former might be homotaxial 

 with C^ of the Avon Section. The latter is probably at a much 

 higher horizon. 



A table is appended (pp. 64-67) with names of species, localities, 

 and thf Scottish horizons. These latter are, for the greater part, 

 called after the characteristic limestone ; the fossils, however, are 

 by no means restricted to that stratum, but are frequently found 

 in the associated shales. There being ver}^ few records outside 

 Scotland, it has not been considered necessary to give additional 

 columns for their horizons, more especially as they are not very pre- 

 cisely defined at present. Since the localities are full}" dealt with 

 here, they are given under the descriptions only in the case of 

 holotypes and rarer species. Also those alone from which I have 

 actually seen specimens myself are stated. I have examined many 

 of the gasteropoda to which names have been given in the Scottish 

 Greological-Survey lists, and I find that these names are not in all 

 cases to be depended upon. Confusion has probably arisen from 

 grafting more recent nomenclature on the older. For instance, 

 I have met with five distinct species referable to at least two 

 genera, all grouped under one specific name,- which was not 

 applicable to any one of them. On the other hand, a single species 

 occurs under two different names. 



In order to save space, onty such parts of tlie synonymy are 

 re])eated as are essential for clearness. 



Most of the small specimens were drawn with the camera lucida 

 on the microscope, and the approximate magnification is given in 

 each case. 



For the loan of specimens I offer my most hearty thanks to 

 those in charge of the Greological Survey Collections in London 

 and Edinburgh; to the Council of the Hancock Museum, New- 

 castle-upon-Tyne ; to the late Prof. McKenny Hughes, Sedgwick 

 Museum, Cambridge; to Dr. Ritchie, Royal Scottish Museum, 

 Edinburgh ; to Mr. Peter Macnair, Glasgow Museum, Kelvin- 

 grove ; and to Mr. Herbert Bolton, Bristol Museum. I desire 

 also to express my gratitude to Mr. Robert Dunlop, Dunfermline, 



