L5Q \<</n<d Society: — 



hypersthenitc is also intrusive. The author found no hypersthene. 

 There are two varieties: — one a remarkable rock, consisting mainly 

 of large crystals of diallage, a gabbro extremely rich in this mineral 

 and almost free from felspar ; and a gabbro of later date, much re- 

 sembling the ordinary gabbro of the Lizard, the felspar being con- 

 verted into a kind of saussurite, and some of the diallage into horn- 

 blende. The " felspar-porphyries " appeared to the author in the 

 field to present all the characters of true igneous rock, to be asso- 

 ciated with tuffs, and to be unconformable with the above-described 

 group of rocks. Microscopic examination placed their igneous cha- 

 racter beyond doubt. There are also some basalt dykes of later date 

 than the above. The author is accordingly of opinion that the prin- 

 cipal conclusions of the paper referred to above are not warranted 

 by cither stratigraphical or lithological evidence. He considers it 

 probable that the " felspar-porphyry," like so much of that in 

 Scotland, is of Old-Red-Sandstone age, and that the serpentine is of 

 later date, but Palaeozoic. 



2. " On the Metamorphic and overlying Rocks in the neighbour- 

 hood of Loch Maree, Ross-shire." By Henry Hicks, M.D., F.G.S. 



The rocks in the neighbourhood of Loch Maree have been described 

 by various authors, but chiefly and most recently in papers commu- 

 nicated to the Geological Society by Prof. Xieol, of Aberdeen, and 

 by Sir R. Murchison and Prof. Geikie, of Edinburgh. The views 

 held by these authors in regard to the order of superposition of the 

 rocks are well known to be greatly at variance, not only as regards 

 some of the minor subdivisions, but in relation to the actual age of 

 nearly the whole of the rocks to the east, or those forming the Cen- 

 tral Highlands. The older geologists and, more • recently, Prof. 

 Nicol hold the view that the Central Highlands consist almost en- 

 tirely of the old fundamental (pre -Cambrian) gneiss, or rocks of that 

 age ; whilst others, represented by the late Sir R. ILurchison and by 

 Prof. Geikie, say that the rocks forming the whole of the Central 

 Highlands are of much later date, and for the most part of Silurian 

 age. In the present communication the author endeavours to show, 

 from results obtained by him recently by a careful examination of 

 a section extending from Loch Maree to Ben Pyn, near Auchnasheen, 

 that the interpretations previously given are in some important 

 points incorrect, and that this has been to a great extent the cause 

 of such very diverse opinions. 



The section described by him runs for some miles along the north 

 shores of Loch Maree, is then continued in a S.E. direction along the 

 heights opposite Kilrochewe and across Glyn Laggan, and then in an 

 easterly direction through the heights on the north of Glyn Docherty 

 to Ben Fyn and the range of mountains to the north of Auchna- 

 sheen. 



On the western and for some distance along the north shores of 

 Loch Maree the Lewisian rocks (fundamental-gneiss series) are seen 

 to consist chiefly of reddish or greyish gneiss and hornblende- and 

 mica-schists. The strike in these beds is more or less continuous 



