REPORTS ON EXCURSIONS. 251 



15 ft. in girth and 100 ft. in height. The variety heterophylla 

 of Gastanea sativa appears to be rare on a big tree as a sport. 

 This is the first specimen we have met with. It was also new to 

 Mr. Whitton, and to Mr. Goldring, the landscape gardener who 

 has designed the alterations in the grounds at Finlayston. 



Glen Douglas, 24th August, 1907. — Mr. Archibald Park, 

 conductor. — This excursion, which was arranged jointly with the 

 Geological Society of Glasgow, took place during favourable 

 weather, and was attended by a party of thirty, ten of whom 

 were members of this society. By special arrangement, the 

 party were allowed to leave the train at Glen Douglas Passing- 

 place, so as to obtain ready access to the head of the valley. 



Glen Douglas is supposed to have existed as a very old river 

 valley prior to the formation of Loch Long and Loch Lomond. 

 It is believed that at that period the water-shed was further 

 west than in more recent times, and that the river had its course 

 through Coilessan Glen to Glen Douglas and onward to the 

 Forth. At a later period the valley was deepened by ice-action, 

 as is evidenced by the moraines visible in the glen. Subsequent 

 to the ice age, a barrier to the course of the river was created by 

 deposits of moraine matter, which were probably carried down 

 from the valley on the north side of the glen at Invergroin. A 

 small loch was thus formed, which was afterwards drained as the 

 river gradually cut its way through the obstruction, and the glen 

 assumed its present form. The prevailing rock is mica-schist. 

 No granite is seen in situ; a large boulder visible in the glen 

 appears to have been carried by ice from the hills between Glen 

 Falloch and Glen Fyne. A scar on the face of the cliffs on 

 Tullich Hill, on the north side of Glen Douglas, and a 

 considerable heap of debris near the foot of the hill, bear evidence 

 to a land-slip which has occurred subsequent to the ice period.* 



The Mosses and Microfungi observed in the glen were reported 

 on by Messrs. John R. Lee and D. A. Boyd respectively. 



Montgreenan, 21st September, 1907 ; Craigends, 5th 

 October, 1907; and Erskine, 12th October, 1907.— Mr. R. B. 

 Johnstone, conductor. 



*(See Transactions Nat. Hist. Soc. of Glasyow, v. 283.) 



