Dr. FiTTON on the Strata below the Chalk. 



J 19 



about 

 )• 3 



(22.) In another section of this part of the stratum, at one of the quarries 

 about midway between Risborough and the east of Sandgate*, the detail 

 was thus : 



Surface of the hill. Feet. Inch. Feet. Inch. 



1. A group, consisting of alternate courses of sand and irregular siliceous 



concretions : — 



a. Sand, with a few interspersed concretions 3 



b. Stone, in irregular spongiform concretions, including fragments 



of Oysters or Gryphites, and passing into grey, compact chert, 

 which in some instances graduates into chalcedony ;- — retaining, 

 however, traces of the original sandy structure. The concre- 

 tions include also minute fragments of calcareous matter, so 

 that the surface effervesces in detached points ; about 2 



c. Sand ; loose, somewhat coarse, consisting principally of grains of 



quartz 6 



d. Stone ; in loose spongy concretions, white, opake, and in some 



places more compact within, like chalcedony ; not effervescent. 4 



e. Sand ; coarse, dark brown, not effervescent ; a great part con- 



sisting of grains of translucent quartz 6 



f. Stone ; in roundish, flattened concretions. A conglomerate of gra- 



nules of quartz, with some portions of flinty slate, and dark green 

 specks, cemented by sparry carbonate of lime : from 2 inches to 8 



g. Sand ; dark greenish grey, not effervescent, including casts of 



Ammonites in pyrites 4 



h. Stone 2 



t. Sand ; dark greenish grey, gritty, not effervescent 4^ 



2. A bed of siliceous and porous concretions, nearly continuous ; very like 



the whetstone of Blackdown ; not effervescent 



3. Beds of sand, partially concreted, somewhat coarse, soft, effervescing 



copiously, and including concretions of cherty stone. The false stratifi- 

 cation of this part of the cliff is very conspicuous 



4. Stone, alternating with sand : thus : — 



a. Stone, in somewhat compact concretions, oblique to the general 



stratification, including cylindrical portions, like the stems of 

 Siphonaria ; the greater part siliceous, white and opake, but 

 effervescing in detached spots ; about 9 



b. Sand, greenish grey, effervescing copiously 6 



c. Stone, in loose, spongy, irregular concretions 9 



d. Sand, loose, greenish grey, effervescent 6 



e. Stone, in spongiform concretions, like 1. b. above, passing into 



chert 4 



/. Sand, like d 9 



g. Stone, in spongy concretions ; as at Blackdown 4-' 



}» 



2to4 



1 



3 



about 

 4 



* See the Map, PI. VII. fig. 1. 



