Glasgow Geological Society. 297 



have entered the Clyde at Bowling, and from thence downward con- 

 tinuously to the sea at a depth of more than 200 feet below the 

 present sea-level. Mr. Croll, in assuming that this great deep 

 trough, which extends along the course of the Kelvin valley, and 

 also up the valley of the Clyde to above Glasgow, was scooped out 

 by river action, seems to have lost sight of the fact that on both, 

 sides of the river Clyde, extending from Erskine Ferry to below 

 Bowling, the trap rock comes close to the shores of the river along 

 this tract, narrowing and forming the comparatively shallow bed of 

 the channel which the Clyde Trustees have been engaged deepening 

 for years. This sunken trap ridge of Carboniferous age is a con- 

 tinuation of that forming the Kilpatrick and Renfrewshire range of 

 hills. Mr. Young next pointed out that this low ridge of rock 

 would form a barrier across the Clyde valley at this point ; and if, 

 as Mr. Croll supposes, the land there stood 200 or 300 feet above the 

 present sea-level, he (Mr. Young) could not see how the waters of 

 the Clyde, into which the Kelvin, Cart, and other streams flow, 

 could ever have reached the sea outside until they reached the 

 height of the lowest portion of this rock-barrier at Bowling; nor 

 could the sea, even at a later period, ever have obtained access into 

 the upper reaches of the Clyde, eastward of the barrier, until 

 this rocky ridge was depressed beneath the sea-level, which was 

 probably during the Glacial period, and in which there is evi- 

 dence, from the marine shells found at Paisley and elsewhere, 

 that marine conditions prevailed, in reaches of the Clyde east- 

 ward of the barrier, as far up the river as Glasgow. At present 

 this barrier at Bowling has been reduced by erosion and man's 

 agency to a depth of from twenty to thirty feet below the 

 level of the river, but it must be at least still 200 feet above the 

 bottom of the deep rock basin which stretches eastward up the 

 Clyde and Kelvin valleys, as revealed by the bores. Mr. Young 

 showed that this rock-basin, previous to its being filled up by recent 

 sediments, must have existed as a deep lake, whose waters stood on a 

 level with that of the barrier, just as the present barrier at the 

 mouth of Loch Lomond determines the height of its waters above 

 that of the sea. Mr. Young further stated that a river flowing 

 westward from the watershed at Kilsyth, along the valley of the 

 Kelvin, would, supposing it could be cleared out of its present 

 surface deposits, have only to run down a sloping channel to the 

 depth of 100 feet, when it would hav^e entered the great lake, whose 

 bottom at many places was more than 300 feet below the level of 

 the above watershed, and whose waters, while the land stood higher, 

 would always be on the level of the barrier at Bowling. 



II. Ordinary meeting, April 14th. — Prof. J. Young, M.D., F.G.S., 

 &c.. President, in the chair. — Mr. J. Croll communicated a letter in 

 reference to some remarks recently made by Mr. John Young on his 

 paper, entitled, " On two river-channels buried under drift," &o. 

 Mr. Young had stated that the deep hollow which he (Mr. Croll) had 

 every reason to believe was the ancient bed of the- Kelvin, was 

 ascertained by a bora at Drumry to be no less than 230 feet below 



