NATURAL HISTORY SOCIETY OF GLASGOW. 151 



woodpecker (Picus major), shot at Archerfield, and now in the 

 possession of the Right Hon. R. C. Nisbet Hamilton, at that 

 place; the smew (Mergus albellus), and the Egyjjtian goose (Anser 

 Egijptiams), both shot by Lord Binning at Tyninghame; the 

 shoveller [Anas dypeata); the gad wall (Anas strepera), etc. In 

 connection with many of the species included in the list, Lord 

 Binning communicated highly interesting notes on their occurrence 

 and habits; and closed his remarks with a very spirited account 

 of a live specimen of Pallas' sand grouse (Syrrhapfes paradoxus) 

 which he had kept in confinement about eighteen months. 



IIL—On the Geology of Ailsa Craig. 

 By Mr W. Newton MacCartney. 



According to the Ordnance Survey this island attains a height 

 of 1114 feet. Dr Bryce makes its length 3300 feet, and its 

 breadth 2200 feet. The circumference of the island is nearly 

 three miles. The north and west faces are very steep; while the 

 south and east assume terraced forms, and, to ordinary climbers, 

 are very easy of ascent. On the steep faces vegetation is 

 barren, and consists almost entirely of small wiry grass; while, 

 on the sloping ascent, many wild flowers and mosses may be 

 culled. The visitor, in climbing the rock, ascends a sloping 

 pathway to the terrace, on which stands a ruined castle. Above 

 this terrace is another called the Castle Walk, and again a larger 

 terrace, having in wet seasons a little lochan of water, and in all 

 seasons a soft wet mossy patch, always kept moist by the surface - 

 draina2:e of the rock, which is shrouded often in mist and cloud. 

 From this terrace, a winding gorge makes the climb to the top 

 comparatively easy, from which, on a clear day, a view may be 

 had which will repay a few hours' sea sickness, and a good hour's 

 stifi" climb. 



The rock is columnar syenite, composed of felspar, horn-blende, 

 and small quantities of quartz. I am certain that there is no 

 amorphous rock on the island, except the trap dykes, mentioned 

 hereafter; and the errors made by MacCulloch and Bryce can 

 easily be accounted for when we make allowance for the shortness 

 of their visits, and the great difficulty there is in tracing out the 

 columnar form under the heaps of stone which cover the southern 

 and eastern slopes of the rock, but if such a particular examination 

 is made, the columnar structure can easily be noticed. The rock 



