The Geology of the Cluden Basin. 135 



that at the outset I was compelled to reject the Survey's conclu- 

 sions. In order to account satisfactorily for all the deposits in 

 the basin, I found that a more comprehensive theory was re(]uired 

 ■ — one which would at once send us back to Nature for facts to 

 verify or reject its claims. Briefly it may be stated thus: — 



Above Roughtree School stretches the original valley and 

 stream, both of pre-glacial age. From the school down to 

 Woodlands and Newbridge there is an underi_\ing sea-ljeach or 

 marine terrace a hundred feet abo\'e the present sea le\el. At 

 Midnuiuierv, Newluidge, and Holywood Church there is a rapid 

 descent to the 50 feet terrace, which occupies the remainder of 

 the basin. Both of these terraces were traversed by glaciers, and 

 are now covered l)y their deposits. When the ice disappeared the 

 Cluden was unalde to regain its former channel, but was com- 

 pelled to car\'e another. Facts proving this theory were at first 

 both few and doubtful, but they are now more than ample. The 

 pure sea sand oT the 100 feet beach turns up in the most unlikely 

 places. That sacred .spot containing the martyrs' graves affords 

 the most conclusi^•e evidence, and establishes the sequence of 

 the deposits as marine, glacial, and fluvial. A cross section 

 would show a ridge of glacial gra\'el resting upon a thick deposit 

 of marine sand adjoining a later terrace of river mud. The 

 mound is rounded on every side — an impossibility with a denuded 

 terrace; there are no lateral streams to denude it; there is a 

 sharp line of demarcation right round its base, exceptional in 

 river plains but peculiar to gracial depo.sits ; its long axis corre- 

 .sponds to the direction of the valley; and its material consists of 

 the usual glacial debris, rounded and scratched stones of all sizes 

 precipitated without stratification or bedding. At Hallhills, 

 further up the river, abo\e the 100 feet contour line, the marine 

 sand is absent, while the upper end of the ridge is truncated by 

 the river. At Baltersan the marine sand is present, tlie broken 

 end also facing up the \alley. In a field at the manse the sand 

 has been (juarried. The church\ard, with its oj^en graves, gives 

 both deposits in their respective positions. All along the river 

 gorge there is a stratum of fine sand lietween the overlying 

 glacial gravel and the solid rock beneath. At Cluden Bank 

 disused quarry, where the descent from the 100 feet to the 50 

 feet beach is effected, the marine deposit is quite distinct on both 

 sides of the river. The 50 feet platform is well displayed in a 



