298 Reports and Proceedings. 



the present sea level ; and that for several miles to the east and west 

 of this place it was nearly as deep. Consequently, if this hollow 

 was an old river channel, it must enter the Clyde somewhere near 

 to Bowling, at a depth, below the present sea level, of upwards of 

 200 feet, and, " if so, then it followed that the rocky bed of the 

 ancient Clyde must be buried under more than 200 feet of surface 

 deposits, from Bowling downwards to the sea." Nothing was 

 inferred by Mr. Croll regarding what may have been the condition 

 of the Clyde above Bowling, consequently Mr. Young's objections, 

 grounded upon the supposition of a rocky barrier crossing the Clyde 

 below Erskine Ferry, had absolutely nothing to do with the question 

 at issue. 



Mr. James Geikie, vice-President, then made a few remarks, stat- 

 ing that he had visited the localities mentioned in Mr. CroU's letter, 

 and that he objected to some of Mr. Young's statements. It was not 

 the case that trap-rock occurred in the bed of the Clyde at Erskine 

 Ferry, neither did it come close to the shores of the river at this 

 place so as to narrow the channel ; and, as no rock was met with 

 between this point and the sea, it was quite gratuitous to assume that 

 the river flowed over a shallow rocky bed. Neither in bores nor in 

 dredgings had anything save mud, sand, clay, and gravel been met 

 with in the Channel of the Clyde, between Erskine Ferry and 

 Bowling. The fact was that the hills only approached close to the 

 river at Bowling, and even here there was sufficient room between 

 the lip of the river and where the rock appeared on the southern 

 shore for a broad river channel to be buried. Mr. Geikie had pro- 

 tracted the slopes of the hills at Bowling, and found that, by con- 

 tinuing the angle formed by the inclination of the hills on both 

 sides, we could not have a less depth than from 250 feet to 280 feet 

 of drift deposits lying in the centre of the valley at this place. This 

 result fully bore out the conclusions arrived at by Mr. Croll in his 

 paper. Mr. Geikie then went on to say that the only place where 

 rock actually occurred in the bed of the Clyde was at Elderslie, near 

 Eenfrew Ferry. Mr. Deas, resident engineer to the Trustees of the 

 Clyde Navigation, had kindly allowed him to inspect the charts and 

 bores in his office, and from these it was apparent that at Elderslie 

 the river flowed a short distance upon rock. This rock was part 

 of a bed of dolerite intruded among sedimentary strata of Carbon- 

 iferous limestone age, and Mr. Young was wrong in supposing that 

 it belonged to the Trappean series of the Kilpatrick and Renfrewshire 

 hills. The mere fact of rock crossing the river at Elderslie was no 

 proof whatever for the existence of any such rocky barrier as that 

 imagined by Mr. Young. The alluvial and drift deposits stretched 

 far away to the south and north of Renfrew Ferry, and all over that 

 broad haugh-land no rock appeared. 



Mr. John Young, in reply, explained that the main point he 

 wished, in his former remarks to establish had been that Mi*. Croll, 

 in the map attached to his paper, made the channel of the Kelvin 

 open into the Clyde at Bowling as a deep river gorge, whereas he 

 (Mr. Young) contended that neither the Clyde nor Kelvin could 



