404 Mr Maclaren on Ancient Beaches 7iear Stirling* 



The village called the Bridge of Allan, B, now much resorted to 

 for the Airthrey mineral waters, lies at the foot of the terrace, the 

 south side of which is very steep, and covered with growing wood. 

 Footpaths are cut in various directions on the acclivity. In pass- 

 ing along these we discover sand or gravel at every step, and where 

 a foot or two of the sand happens to be exposed, we observe traces 

 of stratification. On ascending to the top of the acclivity, we do not 

 see what is usually seen on the flanks of mountains, a series of knolls 

 or rounded undulations, rising towards the chain. On the contrary, 

 we find ourselves on a plateau or terrace (a, 6, c, c?, /, section 1, and 

 map), with a surface remarkably uniform and level, and terminating 

 abruptly at the foot of the steep hills R, D, which tower over the 

 Carse here to a height varying from 500 to 800 feet. Looking east- 

 ward, we see several hollows running across the terrace, cut by the 

 action of small streams or other agents, but the eye easily discovers 

 that the separate portions of the terrace rise to the same apparent 

 level. Looking westward, we see a great breach (N in section 1) 

 made across it by the river Allan, but beyond the river, at the dis- 

 tance of a quarter of a mile, the terrace reappears, a, 6, and as 

 nearly as the eye, assisted by a pocket-level, can judge, at precisely 

 the same elevation. 



The well-marked part of the terrace ends on the west at Lecropt 

 Church near h ; on the east, at Lord Abercromby's east gate near/, 

 and at the foot of Abbey Crag e, where the village of Causeyhead is 

 built on it. The distance between these points is two miles. Beds of 

 sandstone rising from beneath Abbey Crag, and dipping eastward at 

 a high angle (e in section 1), are seen in the village ; they are seen 

 again in the bed of the river Allan (N, section 1), two or three yards 

 below the level of the Carse, and again at the level of the Carse near 

 Lecropt Church 6. Except at these points, and in the hill above, 

 rock is nowhere visible. 



The terrace reappears nearly a mile west from Lecropt Church at 

 a, but in a difierent form ; for here it rests on 30 or 40 feet of rock. 

 Above the rock there is a deposit of sand and gravel to the depth 

 of perhaps 30 or 40 feet, and the surface exactly resembles that of 

 the eastern part of the terrace. There are distinct terraces also 

 within the grounds of Blair-Drummond. I was able to distinguish 

 three, with pretty well marked cliffs behind them ; but I cannot 

 speak positively as to their height. 



I measured the height of the terrace at Lecropt Church, and at 

 the mineral well, by means of a pocket-level, fitted with a reflector ; 

 and at both places I found it to be about 92 feet above the Carse. 

 If we add 25 feet for the elevation of the Carse above the surface of 

 the Forth at Stirling, the height of the terrace above the water will 

 be 115 feet. But there is a slight swell to be afterwards noticed, 

 for which 15 feet must be added, raising the entire height to 132 

 feet. My measurements, however, being roughly executed, and with 

 no pretension to minute accuracy, I prefer giving them in fathoms, 

 and shall call this the " 22 fathom terrace." 



