1863.] 



DAY LIAS OF DORSETSHIRE. 



281 



(d, the " Belemnite-stone ") by which they are capped. Above this 

 stone there are some 15 or 20 feet more of grey marl (c), upon 

 which rests the base of the Cretaceons Series. 



Fig*. 1. — Vertical Section of the Middle Lias at Black Ven. 



feet. 



a. Greensand, chert, and Drift, about . . 230 



b. Green Ammonite-nodules. 



c. Grey marl 20 



d. The Belemnite -stone. 



e. The Belemnite-shale 



/. Grey marl 1G to 20 



g. Impure limestones, in uncertain and ir- 

 regular beds formed by the induration of 

 the light-coloured calcareous marls 14 to 18 



h. Blue marl containing Belemnites longis- 

 simus, Miller 32 



i. Limestone and marl with Belemnifes. 



1c. Limestone and marl with Ammonites 

 raricostatus. 



I. Lower Lias about 180 



The Lias thus terminates in Black Ven at a height of about 270 

 feet above the sea. The road from Lyme to Charmouth, where it 

 passes through the east " Cuts," is about 70 feet above the highest 

 of the Lias. Prom this point the beds are somewhat steeply denuded 

 towards the valley of the Char, so that we soon lose the Middle Lias. 

 The Lower Lias beds dip gently in the same direction, that is, to- 

 wards the east ; and, at the mouth of the river, we find a fault which 

 throws them down some 50 feet more in the same direction. 



2. Stonebarrow Hill and Westhay Cliff.— The base of the Middle 

 Lias is met with in Stonebarrow Hill at the height of about 80 feet 

 above the sea (m, fig. 2), and the Belemnite-stone (g) at about 

 80 feet above that again. At 16 feet over the Belemnite-stone we 

 find the first layer of the " Green Ammonite-beds " (e)— thus termed 

 by collectors from the green tint of the calc-spar that fills the cham- 

 bers of the Ammonites laticostatus, Sow., the characteristic fossil. 

 Several layers of these limestone-nodules occur in the next 16 or 

 20 feet. Some of the layers are more persistent than others, and all 

 are not equally fossiliferous. 



Above these nodules the marls continue of the same character 

 as in the upper part of the last section (fig. 1) for 75 feet more (d, 



