104 H. B. Woodward — Geology of M., S., 8f L. Railway. 



as might have been obtained from the Boulder-clay. It may be 

 remarked that similar coarse gravels occur near Buckingham in 

 association with the Boulder-clay, and near the margin of the ai-ea 

 over which the ice which accumulated the Chalky Boulder-clay 

 formerly extended. 



South-west of Glebe Farm another cutting showed Great Oolite 

 limestones and marls, the stone-beds being poor and rotten, with 

 seams of pale greenish marl. These beds were burned for lime at 

 the old kiln on the west side of the railway. Further on towards 

 Brackley the top beds of Great Oolite are hard, even-bedded shell- 

 limestones, like beds of Forest Marble ; while below are banded 

 white, brown, and grey marly beds, and soft marly limestones, 

 15 feet thick, the strata being locally disturbed by a number of tiny 

 step-faults, the result, perhaps, of land-slipping. Underneath these 

 beds were very fossiliferous, soft, white limestones and marls, with 

 many specimens of Pholadomya deltoidea ; also Pecten amndatus, 

 Cypricardia, Ostrea Soioerbyi, and other Lamellibranchs ; Natica 

 globosa, N. neritoidea, Terebratula maxillata, and Clypeus. 



Crossing the river Ouse, similar beds of Great Oolite were opened 

 up, some layei's of the rock resembling the Helmdon Stone before 

 mentioned. The section in the cutting was as follows : — 



ft. in. 



Eubble and shivered beds of Great Oolite 10 



Harder bands of limestone, with intermediate marl (2 or 3 feet) ; 



many fossils — Pholadomya, Natica, Clypeus, etc. ... 9 



Banded marly beds and soft white limestone 10 



The beds change in character somewhat rapidly, as soft, pale, marly 

 limestones develop into harder stone-beds irrespective of clay- 

 cappings. West of Grovehill Farm, a section of Great Oolite similar 

 to that last mentioned was exposed. 



It is noteworthy that no Drift occurred along the line of railway 

 in the immediate neighbourhood of Brackley. 



Crossing the Banbury branch of the London and North-Western 

 Eailway, we enter another cutting in Great Oolite. The uppermost 

 beds were one foot of grey marl and " race," resting, on hard shelly 

 limestones (1 ft. 3 in.), like the beds north of Brackley ; and the 

 underlying beds were also similar, including grey clays and white 

 fossiliferous oolitic limestones, with Ostrea abundant, Natica, and 

 other fossils. An irregular bed of gravelly clay and ochreous sandy 

 gravel, 2 to 15 feet thick, rests on the Oolite. Where the gravel is 

 thickest, it has patches of Boulder-clay here and there at the base. 



East of Mixbury there is a long shallow cutting in Gravel. At 

 the northern end the Great Oolite, comprising a few feet of hard 

 white limestone weathered into rubble, is overlain by grey clay, and 

 this clay appears to belong to the Oolitic series. It contains a few 

 pebbles, and these have in all probability been derived from the 

 overlying Gravel. In dry weather, when clays become deeply 

 fissured, stones from an overlying Drift or soil may drop into 

 crevices and eventually become imbedded in the mass of the clay, 

 even to a depth of four or five feet, or more. Portions of this long 



