HABDWICKE'S SCIENCE-GOSSIP. 



193 



THE GEOLOGY OF GLASGOW AND THE NEIGHBOURHOOD. 



B y B . L. JACK, E. G. S. (of the Geological Survey). 



N the present day 

 "the neighbour- 

 hood of Glas- 

 gow" is a very 

 flexible expres- 

 sion. Eor our 

 purpose, how- 

 ever, it may be 

 to restrict the 

 of the term to 

 such localities as would by 

 preference be visited from 

 Glasgow rather than from 

 Edinburgh, or Perth, or any 

 other place where a stranger 

 would be likely to settle. 



In and around the city 

 itself there is more to 

 interest the geologist than 

 would at first be expected. 

 Hardly a day passes when 

 the common device " Street under repair" does not 

 meet the eye in some crowded thoroughfare. There 

 is a fascination, which hardly the busiest can resist, 

 impelling meu to look into holes. But the average 

 bystander departs gravely aud sadly, as from a 

 problem solved, after satisfying himself as to the 

 object of the excavation. Beside such holes in 

 Glasgow, however, the geologist sometimes lingers 

 with a nobler curiosity, for every spadeful thrown 

 up furnishes him with food for reflection. Occa- 

 sionally a "glaciated rock-surface is laid bare, or the 

 outcrop of a coal-seam greets the eye. But it is 

 generally on recent and post-tertiary geology that 

 light is thrown by street-cuttings. 



Within the last half-century some half a dozen 

 canoes have been dug up within the limits of the 

 city.* As it is a treat rarely accessible to see such 

 relics of our savage predecessors in situ, one of the 



* The precise localities are marked on the Geological Sur- 

 vey Map, Sheet 6, Lanark. 



No. 141. 



canoes may be visited in the Andersonian Univer- 

 sity. They prove (taken together with other finds) 

 that men, using stone implements and fire to hollow 

 out their boats from thp, trunks of trees, inhabited 

 the shores of an estuary before the last slight ele- 

 vation of the land converted the estuary into the 

 site of a city. 



Next in order of age are deposits representing 

 different stages in the Glacial period. Striated 

 rock-surfaces are abundant in the neighbourhood 

 of Glasgow, and mark the passage of a debris-laden. 

 sheet of land ice from the highland mountains over 

 the lowland plains and hill-tops. The striae corre- 

 spond in direction (except in cases of deflection 

 caused by local obstacles) with the sources indicated 

 by the proportions of the stones included in the 

 overlying till or boulder clay. The main ice-sheet 

 bore down upon Glasgow from the north-west, 

 crossing in its passage the by no means inconsider- 

 able hill- range of Kilpatrick, which forms the 

 extensiou of the Campsie Eells westward from 

 Strathblane to Dumbarton. Many visitors to 

 Glasgow may not have had elsewhere so good an 

 opportunity of seeing glacial striae as is afforded 

 here, and it may be well to note a few places 

 where characteristic examples are, or at least till 

 recently were, to be met with. Among them are 

 the Possil and Woodside Quarries and the Necro- 

 polis Hill.* Within an hour by rail beautiful ex- 

 amples may be seen on the Kilpatrick aud Strath- 

 blane hills ;f on the sandstones of Craigend Muir, 

 near Campsie ; on Dumbarton Bock ; in the Town 

 Quarry, Paisley ; on the Braes of Glenifl'er ; on the 

 sandstones skirting the northern slope of the Braes ; 

 or still better at Barmufflock Dam, near Bridge of 

 Weir. A capital idea of the general direction of 

 ice-flow may be gathered from a map in Mr. J. 

 Geikie's work, "The Great Ice Age," showing all 

 the striae hitherto mapped. 



• See the Geological Survey Map, Sheets 1 and 6, Lanark, 

 t Geol. Survey, Sheets 23, Dumbarton; and 27, Stirling. 



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