164 A. J. Jukes-Browne — The Vale of Marshwood. 



Coraraencing with a traverse from west to east throiigli Pilsdon 

 and Lewesdon, and starting the base-line of the Greensand at 

 Seoktor, near Axminster, we find it there to be only about 320 feet 

 above sea-level, and thence it rises gradually eastward till it reaches 

 580 feet at Birdsmoor Gate, 700 feet at the southern end of Pilsdon, 

 and about 770 feet on Lewesdon. Between Lewesdon and Beaniinster 

 there are several faults breaking the Jurassic rocks, but it is not 

 certain that any of them displace the Cretaceous series, and on 

 Hackthorn Hill the base of the Greensand is close to the 500 feet 

 contour. The distance from Lewesdon to this point is four miles, 

 and, assuming the fall to be gradual, it is a little, but not much 

 more, rapid than the rise from the west up to Lewesdon. 



Taking next a traverse through the southern outliers near the 

 coast, we find the Cretaceous base-line in Black Ven Cliff at about 

 320 feet above the sea. Thence it rises to about 350 feet in Stone 

 Barrow, and 400 and more on Golden Cap and Langdon Hill, and 

 finally to about 500 feet on Eype Down. Then comes a space of 

 four miles occupied by low ground near Bridport, and when Green- 

 sand is next found on Shipton Hill, its base has fallen to 400 feet, 

 sinking still lower eastward to 300 feet at Askerswell. Along this 

 line of country, then, as along the first, we seem to have a gradual 

 rise and fall in the height of the Cretaceous base-line. 



We will next trace the rise and fall of the same line from north 

 to south. This is best shown on the western side of the area. 

 North of Thorncombe village the base of the Greensand lies at about 

 450 feet, on the south side of that outlier in the same latitude it is 

 nearly 500, by Lambert's Castle it is about 600 feet ; thence it falls 

 to 550 feet below Coney's Castle and to 350 feet at Stonebarrow, 

 2^ miles further south. 



On the eastern side of the district the regularity of the rise is 

 l>roker- by faults, but we find it rising to a maximum of 600 feet 

 on Drakenorth Hill, east of Poorton, falling thence rapidly both to 

 the north and to the south. Even where it is faulted up again on 

 Eggardon Hill it does not seem to get much above 400 feet, and at 

 Combe, near Litton Cheney, it is down to about 300 feet. 



We may fairly assume that the centre of the uplift, or pericline, 

 will be found by di'awing lines between the points where the base- 

 line reaches its greatest height, namely, from Lambert's Castle to 

 Drakenorth Hill, and from Lewesdon to Eype Down. The inter- 

 section of these lines occurs a little east of Monkswood, above the low 

 ridge which forms the watershed between the Char and the head 

 branch of the Simene brook. We may take this spot as the 

 approximate centre of the pericline, which appears to have an 

 elliptical shape, its longest axis being from east to west and its 

 shortest from north to south. We can even form a good estimate 

 of the height to which the base of the Greensand reached over this 

 centre by prolonging the actual rise of the base-line in the Pilsdon 

 outlier, for at the north end of Blackdown, by Stony Knap, it is at 

 500 feet, rising thence to 700 feet below the Pen, and if this rise 

 were continued south-eastward to the spot above mentioned it would 



