Reports and Proceedings — Oeological Society of London. 329 



'^ Upper Lias ' is really the equivalent of the Upper Lias, Cotteswold 

 Sands, and Cephalopod Bed of the Cotteswolds ; of part of the 

 Junction Bed, the Upper Lias, and Bridport Sands of the Dorset 

 coast; and of the Toarcian of Normandy. Measured thicknesses 

 of the strata at four localities in the Cotteswolds are given, and 

 sections to show that an anticline was formed, and p&necon- 

 temporaneous erosion took place at Birdlip before the Scissi hemera. 

 A table of comparative thicknesses of deposits laid down during 

 similar times in the Cotteswolds and Dorset is also given, and 

 u section of the Toarcian at May-sur-Orne, and of the Toarcian 

 and Aalenian strata at Tilly-sur-Seuilles (Calvados), where the 

 Toarcian is reduced to a thickness of only some 23 feet. The 

 chronometry of the Toarcian is discussed, and the approximate 

 maxima of deposit formed during the hemerse Falciferi to Moorei 

 are given, amounting to a total of 719 feet. This time is divided 

 into nine hemerge, so that the time-value of a hemera is equal to the 

 average time taken to deposit about 80 feet of strata. A concluding 

 table gives the sequence and correlation of the following deposits : — 

 The Cotteswold Sands, the Sands at Sodbury, the Midford Sands, 

 those of Cole (Somerset), the Yeovil Sands, the Bridport Sands, 

 and the Northampton Sands. 



3. " Two Toarcian Ammonites." By S. S. Buckman, Esq., F.G.S. 



Two Ammonites belonging to the family Hildoceratidse, found by 

 members of the Cotteswold Naturalists' Field Club, are described 

 and named. The allies of both species have been figured in the 

 " Monograph of Inferior Oolite Ammonites." One is near to Denck- 

 mannia torquata, but the degenerative change begins at an earlier 

 age, and it soon shows marked decline of ornament of which that 

 species gives little information. Its date of existence is probably 

 hemera Variabilis. The other is a platygyral costate degenerative 

 of CJiartonia binodata ; the inner whorls should be the morphic 

 -representations of that species, the outer whorls show a costate 

 stage which is the general rule of decline from a tuberculate stage. 

 Notes are given explaining the technical terms employed. 



The Council have awarded the proceeds of the Daniel Pidgeon 

 Fund for 1903 to Dr. E. W. Skeats, F.G.S., of the Koyal College 

 of Science. 



IL— June 10th, 1903. — J. J. H. Teall, Esq., M.A„ F.E.S., 



Vice-President, in the Chair. The following communications 

 were read : — 



1. " On Primary and Secondary Devitrification in Glassy Igneous 

 Eocks." By Professor T. G. Bonney, D.Sc, LL.D., F.E.S., F.G.S., 

 and John Parkinson, Esq., F.G.S. 



Part I. — By John Parkinson, Esq. 



In this part the types of primary devitrification as found at 

 Obsidian Cliff are briefly reviewed, with the order in which they 



