Geological Society of London. 139 



with. Difficulties attending the determination of the origin of some 

 clastic rocks were also pointed out, and the value of certain structural 

 characters in their diagnosis were mentioned. Assumptions as 

 to the origin of some fragmentary rocks were shown to be un- 

 demonstrable in certain cases, although such assumptions often 

 carried much probability with them. The resemblances presented 

 by de vitrified rhyolitic rocks, fel stones, and felspathic grits were 

 dwelt upon at some length. The paper included a short structural 

 classification of the constituents of rocks. 



2. "Distribution of the Serpentine and associated Eocks, with 

 their Metallic Ores, in Newfoundland." By Alexander Murray, Esq., 

 C.M.G., F.G.S. 



The author stated that no extensive display of serpentine is known 

 in the Laurentian series in Newfoundland ; nor is the existence of 

 crystalline limestone of that age, with which serpentine is often 

 associated, as yet well established. The Intermediate or Huronian 

 system is singularly barren in lime, magnesian minerals, and mica ; 

 lime occurring almost exclusively as intersecting calcareous veins. 

 Over all the known area of the system no masses of serpentine have 

 been observed, and only one instance of the presence of a serpen- 

 tinous mineral, which occurs in an intrusive mass intersecting the 

 Intermediate system, and disturbing the outcrop of the sandstones 

 of the Primordial Silurian (Lingula Flags) at a place called " The 

 Broad " of Tickel Harbour, Trinity Bay, where some steatite with 

 some seams of asbestos were seen near the contact. Wherever a 

 typical fossiliferous horizon could be established, the stratigraphical 

 position of the fossils placed those of the Levis age, or older, below 

 the serpentines ; while in all cases, where the types were of Hudson- 

 Eiver or newer date, they as invariably succeeded unconformably 

 above. Instances of this unconformable relation were mentioned in 

 which the upper formation was as late as the Devonian age. The 

 stratigraphical and palaeontological break between the Levis and 

 Trenton groups is here filled up by a metamorphic mass which, in 

 part at least, may possibly represent the horizon of the Chazy group ; 

 and the great intrusive masses have been connected with, or the 

 cause of, the metamorphic phenomena displayed. 



II. — February 5, 1879. — The President announced the receipt of 

 a legacy of £1000, bequeathed to the Society by the late Sydney 

 Ellis, Esq., of The Park, Nottingham. 



The following communications were read : — ■ 



1. " On the Occurrence of Pebbles with Upper-Ludlow Fossils in 

 the Lower Carboniferous Conglomerates of North Wales." By Aubrev 

 Strahan, Esq., M.A., F.G.S., and Alfred 0. Walker, Esq., F.L.S. 



The authors described the mode of occurrence near Abergele of 

 certain Lower Carboniferous conglomerates, best exposed in Fi'ernant 

 Dingle, and especially of one containing numerous red and green 

 sandstone pebbles, which inclose fossils of Upper-Ludlow forms, 

 and lying above the so-called " Bastard Limestone." From the ar- 

 rangement of the beds the authors believe that they may have been 



