Geological Society of London. 381 



detected by the author, either as a fresh mineral or in the condition 

 of a pseudomorph. The three principal constituents have been 

 isolated by means of the Sonstadt solution and a weak bar-magnet, 

 and separate analyses are given in the paper. The felspar, if of one 

 species, must be allied to andesine ; the opaque iron-ore is strongly 

 magnetic, and contains 33 per cent, of titanic acid. The prevailing 

 pyroxene developes a laminated structure, parallel to the basal plane, 

 by alteration. In composition it deviates in the most marked 

 manner from the rule laid down by Tschermak, Mg-j-Fe being 

 greater than Ca. Bulk-analyses of two specimens of the Whin Sill 

 were given, and one of these was calculated out by means of the 

 data supplied by the separate analyses of the three principal con- 

 stituents. 



The rock presents many points of resemblance to the continental 

 diabases. It comes nearest to certain Swedish diabases described 

 by Tornebohm and to the great masses of trap which occur in the 

 Mesozoic strata of the Atlantic border of North America. 



10. " A Critical and Descriptive List of the Oolitic Madreporaria 

 of the Boulonnais." By E. F. Tomes, Esq., RG.S. 



The author commenced with some general remarks upon certain 

 Oolitic genera of Corals, especially Bathycoenia, CyatJiopliora, and 

 Depapliyllum. He stated that his observations upon the Corals of 

 the Great Oolite of the Boulonnais confirm the conclusions as to the 

 palasontological uniformity of that formation based by Dr. Lycett 

 chiefly on the study of the Mollusca. In the Boulogne district the 

 Great Oolite rests immediately upon Paleeozoic rocks, and there are 

 no traces of any Corals of Inferior-Oolite type. Those met with 

 near the bottom of the Great Oolite seem to approach those of the 

 English Cornbrash. After a tabular sketch of the difi'erent beds of 

 Oolitic age in the Boulonnais, the author gave a list of the species 

 as follows : 



From the Great Oolite : — (Eusmilinee) : Discoccenia hononiensis, 

 g. & sp. n. ; Ceratocoenia elongata, g. & sp. n. ; Scyphocoenia stamini- 

 fera and excelsa, g. & sp. n.; Batliyccenia liemisplicerica, sp. n. ; Con- 

 vexastrcea Waltoni, E. & H. ; Cryptocoenia obeliscus, Mich. ; C. plana, 

 sp. n. ; C. Rigauxi, sp. n. ; C. microphyUa, Tomes; Stylina, sp. ; — 

 (Astr^inas) : 3IontUvaltia caryophyllata, Lamx. ; 31. Rigauxi, sp. n. ; 

 CladopJiyllia Babeana, E. & H. ; Septas.trcea rigida, sp. n. ; Confu- 

 sastrcBa Rigauxi, sp. n. ; C. magnifica. Tomes ; ConfusastrcBa, sp. ; 

 Isastrcea limitata, Lamx. ; I. explanata, Goldf. ; I. tuherosa, sp. n. ; 

 Latimceandra, sp. ; L. lotharinga. From. ; — (Poritidas) : Thamnastrcea 

 mammosa, E. & H. ; Anahacia complanata, Defr. ; A. Boucliardi, 

 E. & H. ; Oenabacia stellifera, E. & H. ; Microsolena excelsa, E. & H. 

 From the Coral Eag : — (Eusmilinge) : Stylina, 2 sp. ; — (AstrseinEe) : 

 CalamopliyUia pseudostylina, Mich. ; Rhabdopliyllia PMllipsi, E. & 

 H. ; Thecosmilia annularis, E. & H. ; Confusasircea, sp. ; Dimorpho- 

 phyllia jurensis, Beck. ; Latimceandra sequana. From. ; Isastrcea 

 explanata, Goldf. ; J. helianthoides, Goldf. ; I. portlandica, From. ; — 

 (Fungidfe) : Trochoseris ooUtica, sp. n. ; — (Poritidas) : Thavmastrcea'? 

 lativicea^idroidea, ST^. n. ; T. ? concinna, GoldL ; T. foliaceaf Qiienst. ; 



