GAULT. 63 



Section of the Gault in Compton Bay. 



Feet; 

 Upper Greensand (for details see p. 68). 



f" fHard blue clayey bands with fucoidal 



I I markings alternating with sandy bands, 



I Passage j containing iron pyrites - - - 6 



I Beds. \ Pale blue silty sand or sandy micaceous 

 I I clay with fucoidal markings, weathering 



Gault <; L yellow 30 



Clay, as above, but of a deeper blue - - - 8 



Greenish clay - - - - - - 2 



Blue clay as above, with fish-scales, &c. in several 



bands 20 



Blue clay - - - - - - 73 



Carstone (for details see p. 55). 



139 



The passage up from the Gault is illustrated in the accompany- 

 ing sketch (Fig. 14), made in the cliffs at Comptou during the 

 progress of the geological survey of the Island in 1852. 



Fig. 14. 

 Junction of the Upper Greensand and Gault in Compton Bay. 





md 



Ft. In. 



a. Upper Greensand. Hard concretionary band, with phos- 



phatic nodules - - - - - -10 



b. Passage by a bluish sand with thin fucoidal markings, 



into - - - - - - -06 



c. Green sandy band with a few nodules - - - 6 



d. Dark blue sandy clay - - - - - 2 



e. Paler and darker beds with small nodules: Fossils, 



Gryphcea, Vermicularia, Area (rare). 



The passage beds, in the former Edition of this Memoir, were 

 included with the Upper Greensand. Lithologically, however, 

 they are more nearly allied to the Gault, with which they have 

 usually been grouped of later years. 



Downwards the Gault passes into the Carstone as described ou 

 p. 55. In its lower part Mr. Normau observed Inoceramus 

 sulcatus, Natica gaultina, and Ammonites dentatus (var. of A. 

 interruptus, D'Orb.), the last-named occurring as a brittle coal- 



