THE RHATIC BEDS. 7 
are followed upwards become less and less fissile, and, in the 
extreme upper part, insensibly graduate into the overlying Lower 
Lias, a thin layer of which, with its characteristic fossils, is well 
seen in a small claypit near the large section. Here we have the 
strongest indications that change in sedimentation was brought 
about by the physical conditions varying with extreme slowness. 
Until recently it was customary to class the Tea Green Marls 
with the Rheetics, but I am now convinced that the view which 
has lately been maintained by a few geologists, that the Green 
Marls belong to the Trias, is the correct one, but, if this is true, 
the Rheetic Beds, except paleeontologica!ly, do not indicate the 
slow and gradual passage of the Trias to the Lias to the extent 
that is usually asserted. 
I have confined myself in this short paper almost entirely to 
the physical and stratigraphical part of the subject, because, in 
the first place, it has been to me the most interesting, and 
secondly, it has been somewhat neglected by geologists, probably 
for reasons already given. 
The paleontological part of the subject I cannot touch upon 
to-night, except to mention the interesting and curious fact that 
the Rheetic fish are closely related to those of the Trias, whilst 
the invertebrate fauna is of a distinct Liassic facies. You will 
see on the table a few of the characteristic fossils, some of them 
from this neighbourhood. 
The section on the wall shows the relation of the Rhetics of 
Needwood Forest to the underlying Marls. It was constructed a 
good many years ago by my father, from his own levellings, and 
is based upon the one-inch geological maps. 
