146 Geological Society : — 



that the differences are of degree rather than of kind. The special 

 features of the area in question are attributed to the depth at which 

 the change was produced. 



April 12th.— W. H. Hudleston, Esq., M.A., F.R.S., 



President, in the Chair. 



The following communications were read : — 



1. " On some Palaeozoic Ostracoda from Westmoreland." By 

 Prof. T. Rupert Jones, F.R.S., F.G.S. 



2. "On some Palaeozoic Ostracoda from the Girvan district in 

 Ayrshire." By Prof. T. Rupert Jones, F.R.S., F.G.S. 



3. " On the Dwindling and Disappearance of Limestones." By 

 Prank Rutley, Esq., P.G.S. 



The existence of chert between two sheets of eruptive rocks at 

 Mullion Island seemed to the author to require some explanation. 

 Cherts are usually associated with limestones, and the absence of 

 limestones in many cases where cherts are found points to their 

 removal by underground waters. The older the limestone, the 

 greater the probability of its thickness having dwindled. The 

 thicknesses of the Ordovician, Silurian, Devonian, and Carboniferous 

 Limestones seem to be in the ratio of 1 : 15 : 15 : 100. Many lime- 

 stones once existing in Archaean rocks may have disappeared, as 

 also limestones in later rocks. 



The author comments on the difficulty of distinguishing some 

 cherty rocks from felstones. 



Two Appendices are added to the paper, the first on the trans- 

 ference of lime from older to newer deposits, and the second on the 

 formation of nodular limestone-bands. 



4. " On some Bryozoa from the Inferior Oolite of Shipton Gorge, 

 Dorset.— Part II." By Edwin A. Walford, Esq., P.G.S. 



April 26th.— W. H. Hudleston, Esq., M.A., F.R.S., 



President, in the Chair. 



The following communications were read : — 



1. " The Origin of the Crystalline Schists of the Malvern Hills." 

 By Charles Callaway, D.Sc, M.A., P.G.S. 



This paper is the third of a series of three. In the first 

 of these, published in the Quarterly Journal in 1887, the author 

 contended that many of the gneisses and schists of Malvern were 

 formed out of igneous rocks. In the second, which appeared in the 

 Journal in 1889, he discussed the origin of secondary minerals at 

 shear-zones in the Malvern rocks, and arrived at the conclusion that 

 all the mica and much of the felspar, to say nothing of quartz and 

 other minerals, were of secondary origin. In the present paper the 

 author first pointed out that some of the most important mineral 

 changes described in his second communication — such, for example, 



