Mr. Austen on the Geology of the South-east of Surrey. 69 



it is clearly defined. A clear line without any alternations separates 

 it from the dark-coloured beds of the gault, and though less clearly 

 marked below, yet its range across the country and numerous sec- 

 tions show that its thickness is uniform. A diagonal arrangement 

 of the bedding is very evident in a portion of it. Organic remains 

 are very rare. Mr. Austen has received one curious specimen from 

 Mr. H. Long, — an ironstone cast of the umbilical portion of an am- 

 monite. Fossil wood also occurs. 



b. Middle division. — Next below the ferruginous division of the lower 

 greensand strata are sands with subordinate bands of hard siliceous 

 building stone, which have been fully described, first by Mr. Mur- 

 chison and subsequently by Dr. Fitton. Mr. Austen confines his 

 remarks to the indications which they afford of the condition of 

 things at the period of their deposition. These sands, which at first 

 sight appear non-fossiliferous over large areas, are found on closer 

 examination to contain numerous minute corals of undescribed spe- 

 cies, broken spines of Echinoderms and fragments of bivalve shells ; 

 all these are most abundant in the lines of the Bargate stone. Large 

 specimens of Nautilus radiatus and Ammonites nutfieldiensis occur 

 occasionally, and casts of a species of Mya are constantly found at 

 right angles with the beds, and in the position in which they live. 



Throughout the middle division of the lower greensand the com- 

 ponent beds jjresent a diagonal structure. Many of the changes 

 which have taken place since the deposition of the strata, such as 

 the consolidation of the Bargate nodulates and ragstone, have been 

 in the lines of the cross-stratification. Mr. Austen regards this struc- 

 ture as indicating a moving power which acted constantly in one 

 direction ; and as in this case the inclination of the transverse beds 

 is always southerly, the materials of the middle green deposits appear 

 to have been, during a vast period of time, accumulated in a given 

 direction, and consequently derived from an opposite one. 



c. Argillaceous division (Neocomian). — The beds which rest im- 

 mediately upon the blue Wealden shales of the valley of the Pease 

 marsh consist of brown and yellow clays. The range of these strata 

 at the base of the hills which bound this area is clearly marked, 

 either by several brick-fields or by the prevalence of oak timber ; and 

 sections showing the place in the series which it occupies may be 

 seen near the ford at East Shalford, and the Artington brick-field. 

 These clay strata often run out at the base of the lower greensand, 

 which gives them an appearance of greater thickness than they really 

 possess. 



Though the general character of this portion of the cretaceous 

 series is argillaceous, it contains subordinate nodular concretions in 

 the lines of bedding, of great size and thickness, and cemented 

 into an exceedingly hard rock by calcareous matter. Corals and 

 shells are abundant in these nodules ; indeed these beds seem richer 

 in organic contents than any other portion of the cretaceous series : 

 good specimens however are difficult to obtain, as the outer surfaces 

 of the shells adhere very strongly to the matrix. 



Besides the fossils contained in the calcareous nodules, the inter- 



