SCIENCE-GOSSIP. 



33 



mentary rock, on the island ; has been very much 

 indurated by heat, dips under the trap at the same 

 angle as the latter, and is only separated from it by 

 a few inches of ash. I have called it sheen sand- 

 stone, as when it is broken and the fractured 

 surface held at a certain angle to the light, it is seen 

 to glitter. This peculiar quality is caused by 

 innumerable planes which cut through it, forming 

 what quarrymen and masons call " glessbans." No 

 doubt the cracks were given to it when it was over- 

 flowed by the trap; subsequent infiltration of the 

 joints having produced the glass-bands. If it is not 

 actually converted into quartzite the particles are 

 exceedingly well bound together and break across 

 when a chip is knocked off. As I have said, the 

 sandstone dips under the trap at the same angle as 

 the latter, but if produced — as seen on the exposed 

 part of the shore at least — it would overlay the trap 

 of the island on which the castle is built ; but as 

 the sandstone on the coast of Ayrshire opposite 

 always underlies this quality of trap, these ap- 

 pearances are probably brought about by a 

 hitch, thus : 



ducks, but strange to say these sounds proceed 

 from a number of peregrine falcons who have their 

 eiries amongst the jutting ledges of the highest 

 cliffs. The clamour they make is evidently got up 

 to distract our attention from their young, and we 

 are convinced in this surmise from seeing a young 

 one sitting well up on the rocks in an almost 

 motionless position, a slight movement of the head 

 being now and then visible. So well does this 

 youngster simulate an amygdaloidal cavity in the 

 trap that it took half-an-hour's argument to con- 

 vince some of the party that it was not just part and 

 parcel of the rock. No doubt this faculty of re- 

 maining still in the presence ol danger will be of 

 great service to the young peregrines. In the days 

 of old, the hunters of Hunterston, on the shore 

 opposite, were the king's falconers, and it was 

 from the Wee Cumbrae cliffs that they obtained 

 their supply of falcons, which were tamed and used 

 in hawking. 



At Gull Point there is a "flying buttress" of 

 rock, where the trap has been cut out by the 

 waves of a former sea, leaving a natural arch. 



East 

 Sea level. 



West. 



Trap. Hitch. Sheen Sandstone, Bedded Trap. 



Geological Section in Wee Cumbrae. 



There are several caves on the east side of the 

 island which run into the trap-rock for perhaps 

 more than sixty feet, and were formed during the last 

 depression of the land. We go into one of them 

 and find the entrance both small and downhill for 

 a short distance ; still there is no accumulation of 

 water on the floor, which shows that it must have 

 free passages through the debris which almost 

 blocks up the entrance. A few bones are lying 

 about, but they have all belonged to sheep and 

 may have been recently introduced, but on a 

 former visit to the island I picked up in one of the 

 caves, a split bone which had belonged to a much 

 larger animal. Forsyth, in his " Beauties of Scot- 

 land," says that there are seven caves in the Wee 

 Cumbrae. We count four, and if certain shallow 

 shelters in the rock are to be taken for caves, there 

 will probably be seven, if not more. 



At the south-east corner we go through Balaam's 

 Pass, a narrow fissure cut in the rock by the waves 

 of the twenty-five feet beach, and, turning Gull 

 Point, are immediately in one of the most interesting 

 parts of the island, geologically speaking, the 

 cliffs rising sheer up from the old beach-line to a 

 considerable height. We hear strange noises and 

 conclude we are in the vicinity of a number of wild 



At this part, on the lower face of the cliff, numerous 

 specimens of hulendite are to be obtained. They 

 occur in joints of the rock, never very thick, 

 perhaps a quarter of an inch being the greatest 

 thickness seen. We are indebted to Mr. James 

 Neilson, leader of the geological part of the 

 excursion, who is well acquainted with the geology 

 of the island, for pointing out this, and other 

 mineral treasures. The amygdaloidal cavities here, 

 as well as cracks or joints, are filled with white 

 quartz. Sometimes the quartz is banded and of 

 various colours for a bit, especially that deposited 

 in cavities, the banded part being next the wall of 

 the cavity. In some instances the quartz does not 

 completely fill the cavities, and the interior hollows 

 are bristling with quartz crystals. At this part 

 also, on the shore, is a patch of very amygdaloidal 

 trap, a number of the cavities being filled with 

 pale-pink radiated cluthalite. Many of the cavities 

 at this part are seen to be gathered into clusters. 

 A few white stilbites and agates are got here and 

 there in the Wee Cumbrae trap, but the prevailing 

 mineral is calcite. This sometimes, as is already 

 stated, is in the form of Iceland spar, very pure 

 and giving the double refraction when set over a 

 dot or a line, which shows that the trap of this 



