Geological Structure about Mornington. 43 



course, possible that, as the basalt flowed over the uneven 

 surface of the ground, some localities were left uncovered, and 

 the denudation may be more apparent than real, and that absence 

 of the rock does not imply removal. There is no evidence, for 

 instance, that it ever covered Mount Eliza, which is about 500 feet 

 high, and the probability is that it merely flowed round it, and 

 sent prolongations up the valleys. In one instance, however, we 

 have described what we believe to be a clear instance of denuda- 

 tion of the basalt before the deposition of the marine Eocene, and 

 this is where we described it as overlying the lignites in 

 Balcombe's Bay. 



These periods of denudation clearly indicate a lapse of time, 

 and, in the absence of critical palfeontological evidence, the age 

 of the conglomerates must be left undecided, for we are, as yet, 

 unable to estimate the time which elapsed between their depo- 

 sition and that of the marine Eocene. They may be Eocene or 

 they may be Cretaceous, though in our table we class them as 

 Eocene, but with hesitation. 



Basa/f. 



No petrological examination of the basaltic rock has yet been 

 made, so that its exact nature is still uncertain. The basalt is 

 probably of Eocene age. 



B/i/e Clays, a^c. 



The exact relation of the blue clays to the gypsiferous sandy 

 clays which lie to the south of the cement works is not quite 

 clear. These latter beds pass up into the ferruginous strata 

 which cap the cliffs, whereas the line of demarcation between the 

 ferruginous beds and the blue or yellow clays with fossils is, as a 

 rule, sharp, and, till we examined the fossils of Landslip Point, 

 we were of the opinion that they are of different ages. It seems 

 advisable to regard the beds as mere local modifications of 

 sedimentation, the oxidised condition of the iron being due to 

 greater porosity of the sands. What applies to the ferruginous 

 sands applies with equal force to the gypsiferous sandy clays. 

 In fact, there seems to be some evidence that these do actually 

 overlie the blue clay in Balcombe Bay, for just north of the 

 cement works gypsiferous sands, of a very similar appearance to 



