38 RENFREWSHIRE EXCURSIONS. 



Mimulus luteus, Sedum anglicum, Ranunculus Lenormandi, Ver- 

 bascum Thapsus, and Hypericum perforatum. 



Writing of the physical features of this locality, in describing the 

 second visit which the Society paid to the district, Mr. John Smith, 

 of Monkredding, Kilwinning, says: — "The Calder Water rises 

 between the two Burat hills, 1481 and 1589 feet high respectively, 

 and its source is about seven miles to the south of Greenock. 

 For nine miles it runs over rocks of the trap series, which lie 

 between the calciferous sandstones and the lower carboniferous 

 limestones. After running for about another mile over alluvial 

 deposits of its own making, it enters Castle Semple Loch, which, 

 from the material carried into it from the hills by the Calder, is yearly 

 getting ' smaller and beautifully less,' and will one day become a 

 level meadow like its southern neighbour, the now-drained Barr 

 Loch. The lower part of the glen is bounded to a considerable 

 extent by high mural porphyritic cliffs of a dull purple colour, and 

 showing in parts a rude columnar structure on a large scale. Further 

 up the hills slope down pretty steeply, the slopes being suddenly 

 broken by a sheer descent of ten, twenty, or perhaps thirty feet 

 into the bed of the stream. This last feature shows the amount 

 of work, in the way of excavating, done by the Calder since glacial 

 times. There is very little boulder clay in the Calder Glen, but 

 here and there we did see a small patch of dull purplish till which 

 appears to have been entirely manufactured out of the hill por- 

 phyrites. With one exception all the boulders observed were of 

 local origin, the odd one being a very small boulder or large 

 pebble of vein quartz, in all likelihood brought from the Western 

 Highlands. High on the north-east side of the glen the hill-slopes 

 vanish from view without showing any very remarkable features 

 except the numerous roches moutonnees which are everywhere very 

 apparent. As well as this latter feature, high up on the south-west 

 slope are to be seen long perpendicular ' crag falls,' indicating in 

 a very distinct manner the way the 2000 to 3000 feet thick ice- 

 sheet has acted on the rocks in this district." 



Among plants enumerated in the report of the second excursion 

 to this district are the alternate-leaved golden saxifrage (C/iryso- 

 splem'um alternifoZmm), the heart-leaved valerian (Valeriana 

 pyrenaica), the mossy saxifrage (Saxifraga hypnoides), Alchemilla 

 montana, the common club-moss (Lycopodium clavatum), the 



