4 o MIDDLE ALBIAN STRATIGRAPHY 



By- Pass. Division 4 (iii) contains species of Hoplites (H.) that are found in the upper 

 part of the spathi Subzone, and condensed in the ' upper dentatus-spathi nodule bed ' 

 in the northern Weald. 



In the most northern cut of the old W. field, situated S. of Horton Wood, the top 

 of the spathi Subzone was seen in 4 (iii). This consists of 1 foot 6 inches of shelly clay 

 containing numerous crushed Hoplites (H.) some with well developed lautiform 

 ribbing. The remainder of 4 (iii) in this cut contains numerous Inoceramus con- 

 centricus but no ammonites were found by the author either in these clays or in 4 (iv) . 

 Anahoplites intermedius appears in 5 (i) and this level is taken to mark the base of the 

 intermedins Subzone. 



Before describing the remainder of the Lower Gault here, the correlation of the 

 spathi Subzone sediments with the sequence at Selborne (Owen 1963a ; 43-4) will 

 first be considered (text-fig. 14). Division 3 (i) at the Horton Clay pit contains the 

 same fauna as Beds 1-3 at Selborne. On faunal and lithological grounds, 3 (ii) may 

 be correlated with Bed 4, 3 (iii) with Bed 5, and 3 (iv) with Bed 6 at Selborne. 

 Division 4 at the Horton Clay pit represents Beds 7-9 and the remainder of the 

 sediments of the spathi Subzone not yet exposed at Selborne. The correlation of the 

 Folkestone and Horton Clay pit sections is shown in text-fig. 16. 



intermedius Subzone 



The sediments from the base of 5 (i) to approximately 1 foot (0-305 m.) below the 

 top of 5 (iii), a total thickness of 20 feet (6-096 m.), contain a typical intermedius Sub- 

 zone fauna. The ammonites are quite often of good size (up to 4-5 inches (0-127 m -) 

 in diameter) but crushed flat. Anahoplites intermedius, A. praecox, A. mantelli and 

 A . planus are common to within 6 feet (1-829 m -) °f the top of 5 (iii) but then decline in 

 numbers above, with Inoceramus concentricus becoming the dominant fossil. 



niobe Subzone 



At a level about 1 foot (0-305 m.) below the top of 5 (iii), Dimorphoplites niobe 

 appears sparingly together with Anahoplites planus, Hamites tenuicostatus and 

 numerous /. concentricus. In 5 (iv) partly crushed ammonites and bivalves occur in the 

 cement-stone nodules, and crushed fossils occur in the interstitial clays ; the stony 

 lenticles are original sedimentary features. The ammonites include Anahoplites 

 planus, Dimorphoplites niobe, D. spp. The same fauna occurs in 6 (i) and (ii). The 

 niobe Subzone is represented, therefore, by 9 feet (2-743 m.) of sediments. 



subdelaruei Subzone 



This subzone appears to be represented only within 6 (iii) and has yielded species 

 of Mojsisovicsia including M. subdelaruei and M. remota. 



meandrinus Subzone 



Division 6 (iv) contains shell seams which, near the top, yield pyritised fossils. The 

 fauna is typically that which occurs in Bed IV and the basal few inches of Bed V at 

 Folkestone classified with the meandrinus Subzone. Three shell seams at depths of 

 approximately 2 feet 4 inches (0-711 m.), 3 feet 4 inches (1-016 m.), and 4 feet 4 inches 



