James Saunders — Geology of S. Bedfordshire. 117 



entry is "dip low," "dip flat"; 1 and it is only at the commence- 

 ment of this traverse that I noted " some crushing and contortion 

 near Nara " ; and at its termination at Roru, 2 that the dip, which 

 for the last few miles had been " very low N.E., suddenly rose to 

 50° beyond Mandari, and then became perpendicular." Other 

 traverses in that neighbourhood might be quoted ; they would 

 extend the area without modifying the result. 



If then we find extreme metamorphism in cases where there is no 

 contortion, and great contortion where there is no metamorphism, 

 are we not justified in seriously doubting whether pressure alone, 

 without some other concurrent cause, can produce metamorphism ? 



III. — Notes on the Geology of South Bedfordshire. 

 By James Saunders. 



THE District included under the term "South Bedfordshire" 

 is that which lies between the escarpment of the Lower 

 Greensand and the extreme southern limit of the county. Within 

 this area the portion that has been most closely examined is that 

 through which the Midland Railway passes, every excavation of 

 which has been visited, in many cases frequently, both during the 

 construction of the line, and also subsequently. A section drawn 

 approximately north-west and south-east through the district in 

 question would cover about fifteen miles of country, and the principal 

 strata underlying it are as follows : — 



Oxford Clay and Coralline Oolite, near Ampthill. 



Lower Greensand, Flit wick. 



Gault, near Harrington. 



Chalk Marl, Chalton cutting. 



Totternhoe Stone, ,, ,, 



Lower Chalk, ,, ,, 



Belemnitella plena zone (Lower Chalk) between Leagrave and Luton. 



Melbourn Rock (Middle Chalk) 



Rhynchonella Cuvieri zone (Middle Chalk) ,, ,, ,, 



Middle Chalk, in massive blocks. Cutting S.E. of Luton. 



Chalk Rock (top bed of Middle Chalk). Between Luton and Chiltern Green. 



Upper Chalk, with numerous flints. „ ,, ,, 



Taking these beds in the order in which they are mentioned, 

 which, although it is that of the sequence of formation, is the reverse 

 of that of superposition, it is proposed in the following notes to give 

 a brief account of their leading features, and also of the fossils that 

 have been found in them. 



At Ampthill the excavations for the approaches to the tunnel 

 expose the Oxford Clay and Coralline Oolite. When first opened, 

 the lines of bedding could be distinctly seen, but subsequent 

 weathering has obscured many interesting features. The cuttings 

 exhibit a series of beds of clay, brown at the top, and containing 

 many small crystals of selenite, whilst lower down- the beds are 

 dark blue, and with them are intercalated seams of hard grey lime- 

 stone, from a foot to eighteen inches in thickness. The lower beds 

 have fewer selenite crystals in them, but these are more regular in 

 form and beautiful in appearance. One specimen obtained from the 

 1 Records G.S.I, vol. x. p. 219. 2 Elevation 5250. 



