William Whitaker —The Red Chalk of Norfork. 29 
Although no very definite conclusion seems allowable from this 
table, it will be seen that more than half of the Gault species 
are such as are not peculiar to that formation, but range above it, 
whilst there is only a single species that is peculiar to the Upper 
Greensand. By disregarding everything but the Mollusca the Gault 
gets an advantage. : 
_ As to the number of Gault fossils! Does it prove that the Red 
Rock must be Gault? How so? ‘There are also Upper Greensand 
fossils, though in less number, and there is a goodly proportion of 
Chalk fossils. If the rock represent Gault, and Gault only, how 
are we to account for the occurrence of these fossils belonging to 
higher beds, and somé of which have nowhere been found in 
undoubted Gault? It seems to me that this is fatal to the Gault 
theory, as also to the Upper Greensand one; for whilst we can 
understand how Gault fossils may occur in Chalk (either by deriva- 
tion, or extension of range), it is not so easy to see how a lot of 
Chalk species can have managed to get down into the Gault. It 
should be remembered that this is not a question of a few stray 
specimens ; but one of many specimens and of a number of species, 
known elsewhere as characteristic of the Chalk, and some of which 
have not even been found in the Upper Greensand. It seems to me 
that, knowing certain species existed in the Gault, we need feel no 
great surprise at their continuing to exist in places after the time 
of the Gault, even though in most places that is not the case; whilst 
to suddenly antedate the appearance of a number of species known 
only as occurring in the Chalk, is a different matter. 
Let me give a chronological illustration. We are now in the 
latter part of the 19th century, and the majority of the men now 
living are 19th century men. There are, however, a good many 
18th century men still living; but no one can say that there are 
any of the 20th century! It is not until the 20th century comes 
that we can have 20th century beings, and what will be the case in 
the earliest part of that century? Why, the great majority of people 
will be 19th century creatures, but few will belong to the 2Uth 
century, and there may be a few survivals from the 18th. 
It may be objected to this, that our divisions of time are arbitrary 
—What then are our geological divisions? are not many of them 
arbitrary too? and has not a large amount of arbitrary division been 
exercised at Hunstanton ? 
The possibility of any of the Gault fossils in the Red Chalk having 
been derived has been alluded to I believe by only two ot the authors 
quoted, Seeley and Gunn. I must own to a sort of surprise that 
fossils from older beds are not more often found worked up again in 
newer beds ; but strangely enough one of the best marked of such 
occurrences (outside of that omnium gatherum, the Drift) is one in 
which Gault fossils are largely found in a newer deposit—and that 
deposit is the nodule-bed at the base of the Chalk, in our neighbour- 
ing county, Cambridgeshire. How is it, we may ask, that so greata 
number of Gault fossils occur in the base bed of the Chalk in Cam- 
bridgeshire, ete.? It is because the upper part of the Gault there 
