12 THE EOCENE BEDS 



The LOWER HORIZON of Aizy is especially characterised by the 

 finer sands above mentioned containing Rostellaria Gsoffroyi, Fas- 

 tigiella gibbosula, Ampiillina splendida and other molluscan remains. 



The UPPER HORIZON of Cuise is typically developed at Cuise- 

 la-Motte, and there forms an extensive series of coarse sands, even- 

 bedded in the lower and upper parts of the section, and cross- 

 stratified in the central portion. The false bedding, the lenticular 

 patches of sand, and the condition and species of many of the 

 fossils, indicate here, as elsewhere, that the deposits of this forma- 

 tion had a more or less littoral origin. 



The section given (fig. 4) shows the condition of the beds 

 when we measured them in July, 1890. A section from Ur. 

 Maurice Hovelacque's notes reveals some minor differences, 

 indicating that the beds are more or less lenticular. The section 

 last referred to was measured in 1883. 



The junction with the nummulitic limestone (//^rr^ t< Hards) oi 

 the Calcaire Grossier is well shown. The upper beds are often 

 argillaceous and glauconitic, and are important from an economic 

 point of view, forming a water-bearing bed. 



At Herouval (Oise) the fine sands of the upper Cuise horizon 

 contain a very rich fauna, many species being peculiar to that 

 locality, e.g., Bayatiia heroicvnlensis, and others, though not 

 restricted to this district, are more plentiful, e.g., Cyrena tetragona. 

 In 1889 we saw the following section : — 



Section at Herouval. 



ft. in. ft. in. 

 Drift (?) and vegetable mould . . . 3 o to 4 o 

 Lower Calcaire Grossier . . , , 30 



Glauconitic bed with fish teeth . . 04 



, \ Buff coloured marl ; pockets of shells . 3 O 



^ • y Fine sand, very pure, full of shells . . 40 exposed. 



Base not seen. 



At Liancourt St. Pierre, near Chars, in a very fine white sand, 

 many fine soecies were collected from a small exposure below the 

 bed of debris with shark's teeth, which we shall refer to as consti- 

 tuting the basal portion of the Calcaire Grossier in certain locali- 

 ties. The section measured by us in 1889 was as follows : — 



Section at Liancourt. 

 Vegetable mould. ft. in. ft. in. 



1^ ^" n ^ Marl. Fossiliferous . . . . 9 o to 10 o 



Laic. Gross.) ^ 



Passage \ Sand. Very coarse grained and glau- 1 



Beds, I conitic, full of comminuted v 5 o to 6 o 



Lower Calc. > shells, teeth of Otodus, &c. i 



Gross. to 6«/5. I Sand. Glauconitic, with few, if anv, I o r . , r 

 J n ■ / r-1 ''^.Sut0I36 



de Luise. j fossils. .... I . 



Sables de C ^and. Pale purple, full of small} ^ g 



Cuise ) ''^"^^^ .-. • • • ' 



(. Sand. Glauconitic ... 5 o exposed. 



Base not seen. 



