572 SECTIONAL TRANSACTIONS.— E. 



in a south-westerly direction, to water level on the Clyde, while south of the river 

 heights of over 100 ft. were attained in the S.W. of the city. More than half the 

 area was under the 100-ft. contour, above which large-scale extension of settlement 

 is only recent. 



The geological formations underlying the city are mostly Carboniferous. These 

 are, for a large part, covered over by vast deposits of boulder clay, deposited by an 

 ice sheet which once occupied the urban area, while raised beach deposits occur, 

 especially on the south side of the river, bordering upon the irregular tract of pebbly 

 alluvium stretching on either side of the river. 



The boulder clay has been carved into a large number of drumlins, whose axial 

 directions vary considerably. This lack of definite alignment in the steep and smooth- 

 sided drumlins would be a definite obstacle to the laying of routes and streets, probably 

 accounting, to some extent, for the late occupation of the northern portion of the 

 city. In different localities the raised beaches are well preserved and provide efficient 

 tracks for road construction. 



The post-glacial valley of the Kelvin within the Glasgow area is narrow and deep. 

 This narrowness has allowed of the construction of bridges at various points at com- 

 paratively small cost, while the depth of water and steep valley sides has made dam 

 construction easy and comparatively inexpensive. The large flour mills at Partick 

 Bridge are examples of mills benefiting in this way. 



The beaches formed as the river cut down to succeeding levels in the boulder clay 

 in Kelvingrove are now utilised as promenades in this public park. 



As the small outcrop of Teschenite dolerite in the Necropolis area of S.E. Glasgow 

 is the only known igneous rock formation in the city, and as only sedimentary rocks 

 and deposits are known elsewhere, the digging of building foundations, laying of under- 

 ground cables and drains and the construction of tunnels and railway cuttings is fairly 

 easily carried out at comparatively small cost, even although the walls of tunnels cut 

 in boulder clay have to be reinforced. This is rather important, since the majority 

 of railways leaving the centre of the city in northward and eastward directions must 

 do so underground, for large parts of the way, because of the great irregularity of the 

 topography. The sedimentary nature of underlying rocks allowed the one-time shallow 

 and silted channel of the Clyde to be comparatively easily cleared by dredging and 

 blasting. 



Although the Broomielaw is the natural down-river bridge situation on the Clyde, 

 the outcrop of more resistant rocks in the neighbourhood of Ratherglen would in all 

 probability have decided the building of the harbour in its present position. 



In the neighbourhood of Jamaica Bridge, the 40-ft. contour, limiting the alluvium, 

 retreats northward, enclosing an extensive level area, which at one time had been 

 formed either as an island in the estuary or by the meandering of the former 

 river, and now provides an ideal site for Glasgow's two great railway termini, the 

 Central and St. Enoch Stations. The smaller streams within the urban area, well 

 supplied with water from the higher boulder clay area, formerly drove numerous 

 mills, which old maps reveal to have been the nuclei around wliich settlement congre- 

 gated when the city began to expand. To-day many of these streams have been 

 filled in in parts, or completely so, and now provide routeways for some of our more 

 important thoroughfares. 



The advent of the electric tramcar and motor car has seen the rapid expansion of 

 the populated area into the higher and steeper outlying drumlin areas, as these forms 

 of locomotion have reduced the obstacle offered by steep gradients. 



The large scale movement of coal and iron ore on the Forth and Clyde and Monkland 

 canals formerly did much to promote settlement in the north of the city. However, 

 as these canals have to meander along a course three times the direct distances, their 

 importance rapidly declined with the advent of the railway, and with the partial 

 exhaustion of the Blackband Ironstone in the Carron district. 



The encroachment of settlement upon the higher drumlin area to the north of the 

 city is solely due to the great demand for dwelling houses. This is essentially a 

 residential area, as steep gradients and inability to get a strong head of water excludes 

 industry from these hills. Numerous Carboniferous formation outcrops supply the 

 city with abundant building stone, while the situation of pumping stations at high 

 elevations at Possilpark and Riddrie give the low-lying, densely populated part of 

 the city a copious siphon supply of water. 



In spite of the fact that the N.W. to S.E. trend of the contours gives the city an 

 aspect essentially towards the river, the tendency to separate residential quarter from 



