750 REPORT— 1900. 



■water origin present. Middle Measures, their genercal cliaracter; formed in a 

 series of freshwater lake basins. Fish remains, where found and in what state of 

 preservation; their habits of life ; Elaamobranchs, Teleosteans (and in some cases 

 Dipuoians), commingled, i.e. marine and freshwater tj'pes in same beds (fresh- 

 water) ; Elasmobranchs found in marine and freshwater beds ; Dipnoi only 

 found under freshwater conditions. Teleostean orders. Crossopteryg'ii and 

 Actinopterygii found in both freshwater and marine beds. Conditions under 

 which coals were deposited as bearing on the occurrence and habits of the fish. 

 The swim-bladder of Ccelalacuthus, and its peculiar use to them under certain 

 conditions. Remarks on fish remains ; Elasmobranchii represented by eleven 

 genera and twenty-three species ; Ichthyodorulites by seven genera and eight 

 species ; Dipnoi by two genera and two species ; and the Teleostomi by twelve 

 genera and thirty-rhree species. Tabular list of fish remains showing their 

 stratigraphical distribution ; remarks on above list ; several new fish-bearing coal 

 shales ; the distribution and vertical range of the Yorkshire coal-fishes being thus 

 greatly extended ; several genera and species new to Yorkshire, and others new to 

 science. 



2. On some Fossil Fish from the Millstone Grit Rocks. 

 By Edgar D. Wellburn, F.G.S. 



The Millstone Grits are naturally grouped into three divisions, viz. : (1) Rough 

 Rock ; (2) Middle Grits : (3) Kinder Grits at base. Middle Grits, consisting of 

 grits, sand, shales, subdivided into ABC and D beds, A being uppermost. 

 Pennine Anticline, mostly composed of these rocks, and on Lancashire side at 

 head of Calder Valley, on the south side in a quarry at summit, there is a good 

 exposure of the D shales, and in these shales majority of fish remains found ; a 

 few others having occurred at same horizon at Wadsworth Moor, Sowerby, Kilne 

 House Wood, and Eccup, Yorkshire. Majority of fish in nodular masses, few 

 in shales. Associated with marine fauna. Fish-bearing beds formed under 

 marine estuarian conditions. Fish of great geological and zoological interest, as 

 largely increasing our knowledge of the fish fauna in groups of rocks whose 

 yield of fish remains has hitherto been extremely limited ; and zoologically in fact 

 that (1) one genus and several species are new; (2) one Lower Old Ked Sandstone 

 fish present ; (3) the occurrence of the Lower Carboniferous types, Orodus, 

 Psephodus, Pristodus ; and (4) several genera and species are new to these rocks. 

 Remarks on fish remains. Table of stratigraphical distribution. 



3. The Plutonic Complex of Cnoc-na-Sroine and its Bearing on Current 

 Hypotheses as to the Genesis of Igneous Hocks. By J. J. H. Teall, 

 M.A., F.R.S., Pres.G.S. 



The plutonic complex of Cnoc-na-Sroine begins about five miles south of 

 Inchnadampf, in Sutherlandshire, and extends in a south-easterly direction for 

 about five miles, with an average width of about one mile. It is bounded on the 

 north and south by peat-covered tracts, and is, therefore, more extensive than is 

 indicated by the above figures. It lies in the disturbed zone. The main outcrop 

 of the Ben More thrust lies to the east, but outliers of rocks above this thrust 

 occur to the north and west. The plutonic rocks were intruded into the Durness 

 limestone series, which is locally altered at the junctions to a marble containing 

 silicates of lime and magnesia. 



The central part of the mass is a red soda-granite or quartz-syenite,^ mainly 

 composed of orthoclase and albite (or a closely allied lelspar), with which a little 

 quartz is associated. Ferro-magnesian minerals are almost entirely absent. The 

 peripheral portions are more basic, and include s)-euites, augite-syenites, nepheline- 



' See Geological Magazine for September, 1900, for further petrographical 

 details. 



