522 Reports — Geological Societtj of Glasgow. 



Mr. Smith of Jordanliill, who recorded the discovery in a paper 

 read to the Geological Society in 1850, visited the locality, but does 

 not appear to have seen the brick or shelly clay — only the " superin- 

 cumbent matter which was left lying at the mouth of the well," and 

 which he pronounced to be " true Till." He got some shells, how- 

 ever, from Mr. Eussell, which seems to have been all of one species, 

 Tellina calcarea. From that day to this, though the place had been 

 visited by many geologists, yet, the well being built up, no one is 

 known to have seen or examined this " shelly deposit." Mr. Russell 

 stated that it was about two feet deep in the thickest part, but 

 " tliinned away rapidly on every side," so as to allow the Upper 

 and Lower Till to come together. This had been confirmed by a 

 new well having been sunk within a few yards of the old one 

 without finding any trace of the " shell-bed." In short, it seemed 

 to be quite a limited strip or patch of shelly clay, imbedded in the 

 Till or Boulder-clay. And this appeared to be a very narrow 

 foundation for all that had been built upon the section, namely, 

 a period of severe Arctic conditions and massive land-ice ; then a 

 milder period of deep submergence ; then a re-elevation of the land, 

 and Arctic conditions and massive land-ice once more. 



Mr. Bell commented on the many improbabilities involved in this 

 intervening "deep submergence," whether regarded as due to an 

 actual subsidence and re-elevation of the crust of the earth, or to the 

 mass and attraction of the ice raising the general level of the sea in 

 the Northern hemisphere. The latter was by far the more probable 

 hypothesis, but neither by calculation nor by comparison with the 

 facts presented in Norway and North America did it warrant us in 

 assuming a submergence in this country of anything like 526 feet. 

 Tljere was absolutely no corroborative evidence fur such a sub- 

 mergence, but much that led directly against it. No shells had 

 been found at a similar level in other parts of the Midland Valley, 

 nor in the numerous side valleys, where they would be more likely 

 to be preserved than on this exposed knoll in the centre. None 

 have been found in the Upper Boulder-clay, which, if all this valley 

 had been a sea-bottom before the "second glaciation," should contain 

 abundance of at least shelly fragments. Further, this shelly clay 

 was said to have been deposited during a " mild inter-Glacial 

 period," which would most probably accompany such a submergence; 

 but the only species of shells found in it indicated not mild, but 

 extremely cold conditions, this Tellina being a characteristic Arctic 

 species not now found living in the British seas. In short, he 

 thought the evidence was very strong that this limited and local 

 slielly clay at Chapelhall, taking all we know of it, was not in any 

 true sense a marine bed. The alternative suggestion was that " The 

 layer containing these shells may have been transported (most 

 likely in a frozen condition) by the ice-sheet, as in many other 

 instances to which he referred. This appeared to be by far the 

 most probable account of it ; its position in the track of the old 

 ice-sheet, and in front of an obstruction presented by the highest 

 rising ground in the district, the nature of the organisms, and the 



