576 EEPOET— 1880. 



4. Report on the Carboniferous Polyzoa. — See Reports, p. 76. 



5. Report on the ' Geological Record.^ — See Reports, p. 87. 



6. On the relation to he established between Goasi-line Directions represented 

 by Great Circles on the Globe, and the Localities marhed by JEarfh- 

 qziaJces in Europe. By Jos. P. O'Reilly, G.E., Professor of Mining 

 and Mineralogy, Royal College of Science, Dublin. 



This memoir, based on the following memoirs published by the Royal Irish 

 Academy- — 



No. 1. ' Explanatory Notes and Discussion of the Nature of the Prismatic Forms 

 of a Group of Basalts, Giant's Causeway.' — ILI.Ac. Transactions XXII. Nov. 

 1879. 



No. 2. ' On the Correlation of Lines of Direction on the Earth's surface.' Read 

 before the British Association (1878). — B.I.Ac. Transactions XXI. June 1879. 



No. 3. ' On the Directions of Main Lines of Jointing observable in the Rocks 

 about the Bay of Dublin.— ^./.^4e. Proceedinf/s. 2nd Ser. Vol. III. 

 has for object to compare the earthquakes which have occurred during the years 

 1870-1878 with certain coast-line great circles of direction which traverse Europe, 

 and which, originally traced by tlie author on a globe from the theoretical considera- 

 tions contained in the memoir No. 2, have been transferred to the map of Europe. 

 The memoir shows that certain relations of position do exist between the earth- 

 quake localities and the great circles. Thus, that between two of these great 

 circles, called by him S.E. Sofala Coast-line Direction, and E. Coast of England 

 Direction, there is defined a band of Europe in which lie the earthquake coun- 

 tries: Holland, district about Cologne, AVestphalia, Rhine provinces, Odenwald 

 district. Upper Rhine district, Switzerland, Tyrol, Upper and Lower Italy (nearly 

 entirely), and Sicily ; that is, the greater part of Europe markedly affected by 

 earthquakes. That other great circles traverse them, forming bands equally re- 

 markable as regards earthquake-movements, and, finally, that a very great number 

 of earthquake localities are situated upon these great circle directions, or near their 

 intersections. That there is evidence of these localities tending to develop into 

 rectilineal directions, and, lastly, that outside Europe those great circles traverse 

 districts markedly seismic in character, so that localities thus characterised, and 

 situated on the same great circle of direction, present a certain connection, and may 

 thus be brought into relation with it and with one another, as regards the earth- 

 quakes which may occur at them. 



The author further proposes to define extents of globe-surface affected bj^ earth- 

 quakes by considering them as being limited by such great circle directions 

 traceable a priori on the globe, as proposed by him in his Memoir No. 2. 



7. Oil the Island of Torghatten, By Professor W. J. Sollas, 

 M.A., F.R.8.E., F.G.8. 



The author described the results of a visit which he made to this island in 

 July 1880. 



The platform from which the peak of the island rises is a narrow plain of marine 

 denudation, produced when the island was submerged 375 feet below its pi-esent 

 level. The timnel which traverses it is a sea-cave, excavated between two master- 

 joints. The floor of the cave is covered with angular blocks of gneiss, which have 

 fallen from the roof since the elevation of the cave-floor above the sea-level. The 

 blocks have fallen far more rapidly at the entrances of the cave than in the interior, 

 and, as a consequence, the roof rises from the middle towards each end of the tunnel, 

 and so does the angular debris, which thus forms at each entrance a vast sloping 

 mound. The vast quantity of fallen material is an interesting indication of what 



