310 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



or conglomerate, marked by rifts of false stratification. The top of 

 the bed upon the shore between Cliif-End and Black-Gang Chine, 

 which at first has the appearance of a distinct continuous stratum, 

 consists of one of those coarse masses, but the true compound cha- 

 racter of the group is well-seen on the N.E. of Walpen Chine, at 

 a point accessible only from above. It seems not to be continued 

 farther westward than the Chine. No fossils have been found in it. 



This compound stratum of laminated clay and sand is of import- 

 ance, from its sustaining the undercliif between Walpen and Black- 

 Gang Chines. It recurs very distinctly at Shanklin Chine, and on the 

 shore thence eastward, — where also it supports a similar and remark- 

 able undercliif. 



XIII. Sands of Walpen and Black-Gang TJndercliff. — Nos. 41 to 44. 



The vertical distance from 40, to the ferruginous group 45, which 

 keeps up the streamlet of the cascade at Black-Gang Chine, is about 

 100 feet, of which but a small portion is visible in the cliifs near the 

 Chine ; the rest being concealed in the undercliff, or accessible with 

 difficulty above. This part of the series therefore cannot be well 

 examined in the section near Atherfield ; but the corresponding beds 

 are very distinctly exposed between Bonchurch Cove and Shanklin, 

 and with some important features which are wanting here. 



41. Fi?'st Sand-rock, about 10 feet thick. This is the first bed of 

 pure sand in the ascending series, anticipating as it were the upper 

 division, a great part of which consists of white sand. It is at pre- 

 sent visible only in one place at the base of the upper clifF near Walpen 

 High. It consists of loose, white sand, intershot with thin flakes of 

 grey clay, a compound well-fitted to retain moisture ; and giving way 

 under pressure, while it has immediately above it sand and sand-rock 

 of slight coherency, — the fall of the whole mass and the production 

 of the quagmire in the undercliff on the west of Black-Gang Chine 

 are clearly explained. 



42. Above 41 is a series of beds, about 70 feet thick, imperfectly 

 seen here, and affording very few distinguishable fossils ; in which the 

 succession appeared to be as follows : — 



d. Light green and yellowish sand, giving a bright green trace under ft. in. 

 the pick , 25 9 



c. Brown cohesive sand slightly protuberant, with casts of large 

 Astarte Beaumontii with Pinna, Pecten, and plicated Terebratula 1 6 



b. Greensand, tough and retentive of moisture 12 6 



a. Sand in three divisions, together equal to 29 feet : at the bottom of 

 the lowest bed, immediately above No. 41, is a coarse gravel with peb- 

 bles of quartz and Lydian stone 29 8 



Total thickness of 42 69 5 



43. A prominent portion of the cliffs between 41 and 45 is brown, 

 coarse sand, with a more rugged surface than that of the adjoining 

 cliff, and about 7 feet thick, a. The lower part (3 ft. 6 in.), contain- 

 ing polished particles of brown iron ore, has some resemblance to the 



