302 Geological Society. 



The graptolitic beds occurring in Band 3 of the Mount Partry Beds 

 have yielded nineteen species, which have been determined by Miss G. 

 L. Elles, D.Sc, who considers that they indicate the upper part of the 

 zone of Didymograptus extensus. The commonest species met with 

 are D. extensus, Hall, and D. bifidus, Hall, both species being repre- 

 sented by small mutations. Bounded bodies, which a comparison 

 with the better preserved specimens from the Tourmakeady district 

 shows to be almost certainly radiolaria, were noted in sections of 

 the cherts and shaly beds at several points. 



In a previous description of the rocks of the Tourmakeady 

 district, the term Shangort Beds was applied to a series of grits 

 and tuffs, and the term Tourmakeady Beds to an associated 

 series of calcareous strata which generally take the form of lime- 

 stone-breccias. In the Glensaul district it is not possible to draw 

 a sharp line of distinction between the two rock-types, some of the 

 calcareous gritty tuffs passing into nearly pure limestone; but the 

 Authors retain the terms to indicate the close connexion between 

 the two districts. 



The fossils from the Shangort and Tourmakeady Beds, which have 

 been examined by Mr. F. II. Cowper Beed, show a close resemblance 

 to those of the Tourmakeady district ; but the finding of certain 

 additional forms, especially Nileus armadillo and Niobe sp., has 

 impressed upon Mr. Reed the close connexion between this fauna 

 and that of the Orthoceras Limestone of Sweden, and has convinced 

 him that it is rather of Arenig than of Llandeilo age. The con- 

 clusion is in conformity with the field-evidence, for at one point 

 beds of gritty shale, containing radiolaria and graptolites (indicating 

 the zone of Didymograptus hirundo). occur associated with the tuff 

 of the Shangort Beds. The relegation of the Shangort and Tour- 

 makeady Beds of Glensaul to the Arenig would imply a similar 

 age for those of the Tourmakeady district. 



The Glensaul district contrasts strongly with that of Tourmakeady 

 as regards the character of the crystalline igneous rocks, which are 

 all quartz-felsites, and the Authors believe them to be entirely 

 intrusive. 



Mr. F. R. C. Reed describes one species of Illcenus, one of Niobe, 

 one of Nileus, two of Bathyurus, three of Cheirurus, one of Pliomera, 

 one of Encrinurus, one of Phacops, and a new species of Bath yur el I as. 

 He also describes three species of Orthis, one of Hyolithes, one of 

 llafinesqxiina, one of Camerella, and one of Porambonites, and his 

 conclusions as to the evidence which is furnished by the fauna 

 regarding the age of the beds are mentioned above. 



