GO Geological Society. 



the present level of the Mediterranean. He theri gave an account 

 of the Post-Tertiary deposits in Europe, Asia, and North America, 

 to show their various heights, and especially of the raised beach on 

 Moel Tryfaen in Caernarvonshire, which was from 1170 to 1350 

 feet high. Some of the shells in that deposit were boreal and did 

 not now live in the adjacent sea. The author stated that no 

 shells of a peculiarly northern character had been noticed in the 

 west or south of England. He then questioned the permanence 

 and even the antiquhty of the present oceanic basins, from a con- 

 sideration not only of the fauna which now inhabits the greatest 

 depths, but also of the extent of oscillation which had prevailed 

 everywhere since the Tertiary period. A complete list of the Moel- 

 Tryfaen fossils was given, to the number of 60, besides 3 distinct 

 varieties, of which number 11 were arctic or northern, and the 

 rest lived in Caernarvon Bay. All of these fossils were more or 

 less fragmentary. 



2. " On the Pre-Devonian Bocks of Bohemia." By J. E. Marr, 

 Esq., B.A., E.G.S. 



The author commenced with a brief notice of the Pre-Cambrian rocks, 

 which are gneisses and schistose limestone with intrusive eclogite ; 

 over these lie unconformably green grits, ashes, breccias, hornstones 

 (etage A of Barrande), which the author considers to represent the 

 Harlech Group of Wales. Etage B is unconformable with this, 

 but conformable with C, which contains the " primordial " fauna. 

 D contains the colonies. E to H are Silurian, and more calcareous 

 than those underlying them. The base of the group is unconformable 

 with those beneath. The lithological characters of the various beds 

 were described. The following are the associated igneous rocks — 

 Granite, Quartz felsite, Porphyrite, Mica-trap, Diabase, Diorite, 

 Eclogite. Of these brief descriptions were given. The author gave 

 a comparison of the various shales with English deposits. The Pre- 

 Cambrian Series much resemble the Dimetian and Pebidian of 

 "Wales, the latter being etage A ; etage B, the Harlech ; etage C, 

 the Menevian, probably a deep-water deposit, as is indicated by the 

 abnormal size of the eyes of its Trilobites ; the lowest bed of etage 

 D probably represents part of the Lingula Elags of Britain. D, a, 1, /3 

 seems to represent the Tremadoc shale of Britain, and, like it, 

 contains pisolitic iron-ore. Representatives also of the Arenig and 

 Bala beds are found. A slight unconformity marks the base of the 

 Silurian. Three Graptolitic zones occur. The lowest, or Diplo- 

 graptus zone, identical with the Birkhill shales, contains thirteen 

 species of Graptolites ; the next, or JPriodon zone (four species), 

 resembles the Brathay Flags ; the upper, or Colonies zone (five 

 species), resembles the Upper Coldwell Beds of the Lake-district. 

 Above these follow representatives of Wenlock, Ludlow, and pro- 

 bably of the Passage beds. The author, with the evidence of these, 

 discussed the " colonies " theory of M. Barrande, pointing to the non- 



