38 . Field Meetings. 



wall of the castle is of a dirty greenish yellow caused by the 

 growth of a Lichen ( Lichenoixt parietina) on the stones* 

 This plant only grows on a northern aspect, consequently 

 none of it was found on the other walls. On returning across 

 the Dee a great number of fresh water sponges were noticed 

 on the stones — a curious little species about the size of a 

 shilling, and a quarter of an inch thick, of precisely similar 

 texture to the sponge of commerce. The next place visited 

 was Keltou Hill, the scene of the famous fairs of the 

 olden time, and from the top of it a splendid view of the sur- 

 rounding country was obtained. After a short rest in Mr 

 Grierson's residence, where the}' were shown some antiquarian 

 relics — amongst which were a broadsword, which last saw 

 service on Culladen Moor, and some granite balls, measuiing 

 from 5 to 8 inches in diameter, numbers of which were found 

 round the walls of Threave a few years since — the pai-ty went 

 on by the Kirkcudl ;right road to the Billie's Glen. A fine 

 patch of Geranium pratense was found on the wayside, and 

 a nice white variety of Valeriana dioica. A small burn- 

 side was covered with the poisonous Water-hemlock, and 

 further up grew plentifully the common Butter Burr, which 

 is very local in the district. The Glen would have repaid a 

 much more minute search than could be made. However, 

 some good things were secured. The common Dog's Mei'- 

 cury covered almost the whole of the interior of the Glen, 

 and on the ledges of the rocks were numerous patches of the 

 pink-flowered grass, Melica unifiora. Mr Grierson pointed 

 out a place where earlier in the season that curious little 

 fern, the Moonwort, grows in thousands, but it was then, of 

 course, too late for it. A mine once sunk in expectation of 

 finding lead was pointed out. It is sunk- about 30 yards 

 deep into the east side of the Glen, and the entrance is 

 through a very fine natural arch, which one of the i^arty 

 sketched at the request of Dr Gilchrist. In the field above 

 the Glen some bare rocky knowes were covered with masses 

 of the little white Sedum anglicanum. On others were found 

 the Rock Rose the blue Jasione montana, and the Wood 



