LOWER GREEN SAND. 29 



Group X., or the Upper Gryphsea, group, includes about IG feet* 

 of sand, with some clay. In the lower 12 feet there are several 

 ranges o^ Exogyra simuita, and nodules with Endlhistcr (^Brissus) 

 and Ammonites Martini. The ferruginous matter of this beil is in 

 some places distinctly oolitic, like that of Group IV. The upper 

 part of the group is a greenish sand with Exogyra sinuata, this 

 being the highest point in the Atherfield section which has 

 yielded that species. Small fragments of vegetable remains 

 \Lonchopteris Mantellii) occur not only in these beds, but nearly 

 throughout the entire formation. In the lower part of this 

 group they are associated with Inoceramus. 



Group XL, the Cliff End sands, about 20 feet in thickness, 

 consists of sands with a thin bed of clay with Trigonia dcedalea 

 in the lower part, and in the upper part of dark bluish and green 

 sand, with many cylindrical stem-like and iDranching concretions, 

 containing pyrites. 



Group XII., the Foliated Clay and Sand, consists of thin alter- 

 nations of clean greenish sand, with dark-blue clay, and much 

 pyrites. The bed includes also lenticular masses of coarse 

 current-bedded sand-rock. It is about 25 feet thick, and from its 

 yielding nature forms an extensive undercliff on tlie west side of 

 Blackgang Chine. But it is most clearly exposed to view on the 

 buttress of rock which forms the south side of Walpen Chine, 

 where, however, it can be reached from above only. The dip in 

 this part of the section may be calculated by tracing this bed 

 down to the beach. It amounts to 1 in 26, or a trifle over 2°. 



In general character this group is closely allied to the Sand- 

 rock series, and it was correlated by Dr. Fitton with a bed which 

 has been taken as the base of that series at Shanklin. Traced 

 inland this bed passes by Pyle, Corve, and Kingston, cropping 

 out at the foot of a marked feature all the way [jjostca, p. 30), 

 and thence striking westwards seems to die way in beds 

 distinctly of the ferruginous type. 



Group XIIL, the sands of Walpen Undercliff, is about 97 feet 

 thick. It has at its base a bed of loose white sand or sand-rock, 

 about 10 feet thick, which rises to the top of the cliff on the south 

 side of Walpen Chine. Above this bed, which he calls the First 

 Sand-rock, Dr. Fitton noted the following in descending order : — 



Ft. In. 



Light green and yellowish sand, giving a bright-green streak 



under the pick - - - - - 25 9 



Brown sand with Astarte Beaumontii, Pinna, Pecten, and 



Terebratula - - - - . -16 



Moist greensand - - - - - -12 6 



Sand, based by a coarse gravel with pebbles of quartz and 



Lydian stone - - - - . -29 8 



Above these are brown sands with polished particles of iron-ore, 

 and sands with beds of dark-green or black coherent mud. 



* There are some slight discrepancies in this and other cases between the thick- 

 nesses given in the text and in the table of Dr. Fittou's paper. 



