126 W. D. Lang — Zone of HopUtes interniptus 



The reason why this zone is so rarely exposed in section is that 

 the beds above it are sandy and pervious to rain, and those belonging 

 to it are also to a large extent pervious. On the other hand, the 

 Lias clay upon which it rests is extremely impervious. Consequently 

 the line of junction between this zone and the underlying Lias is 

 marked by a succession of springs, forming boggy ground covered 

 with overgrowth. Sections are therefore of rare occurrence. 



This tract of boggy ground lies on Black Van at a height of over 

 300 feet above sea-level, and from 50 to 100 feet below the new 

 Lyme road. This it crosses on its descent, eastwards of Charmouth 

 cutting, and is not very noticeable as it turns northwards over the 

 old Lyme road. Thence it sweeps round the hillside above and 

 parallel with the Axrainster road, and becomes very obvious in the 

 ields below "Fernhill," where the springs which supply the village 

 lie. Further, this boggy tract can be traced across the Axminster 

 road, in the neighbourhood of Hogchester farm, and so up the 

 valley ; but no inland sections have been found. 



On the eastern side of the Char valley, on Stonebarrow cliff and 

 round Stonebarrow hill, this tract of land is not so obvious, doubtless 

 because the line between the pervious and the impervious is not so 

 clearly defined. For the Cretaceous beds on Stonebarrow cliff rest 

 on the lowermost beds of the zone of Amaltheus margaritatus, 

 Mont., known as the "Three Tiers," ^ which are loamy; whereas 

 on Black Ven they overlie the lower beds of the zone of Liparoceras 

 capricormts (Schlotheim),- which consist of impervious clays. 



The more eastern section on Black Ven shows the junction 

 between the Cretaceous and the Lias. It lies on the cliff face, at 

 a height of about 315 feet, directly beneath the Charmouth end of 

 the Charmouth cutting, where the descent to the village begins. It 

 is covered with fallen Greensand, and was found as follows : — 



The edge of a steep precipice just below the section is formed by 

 the outcrop of a limestone a foot thick, the ' Belemnite Stone.' 

 Above this the cliff face slopes backwards at a moderate angle, 

 and on this slope Lias fossils and worm-tubes from the Cretaceous 

 beds are found mixed. This slope was followed upwards until the 

 highest Lias fossil was found. A foot or so above this a hole was 

 dug, and after clearing away perhaps a foot of loose fallen sand, the 

 junction was hit. The section was measured in December, 1902, 

 and the hole dug was still visible in December, 1903, and easy to find. 

 The details of the section are given in Fig. 1 (p. 125). 

 Bed 1. The pebbles at the base of the black loam do not form 

 a continuous bed, but occur in pockets, which may be six inches 

 thick at the widest part. Between these pockets are spaces where 

 no pebbles occur, but the dark green-black loam is directly super- 

 imposed upon the blue clay of the Lias, forming a contrast, and 

 contains itself so much clay that it is coherent enough to allow quite 

 small specimens to be dug out, showing the junction as a sharp 

 vi^avy line (see Fig. 3, p. 128). 



1 H. B. Woodward: "The Lias of England and Wales," 1893, pp. 195, 196. 



2 H. B. Woodward: loc. cit., p. 68. 



