92 Geological Society of London. 
doctrine, culmiferous rocks distinctly overlying the so-called grau- 
wacke, and not being referable to any of the well defined and normal 
types, which compose the old red sandstone and Silurian system. 
I shall now pass on to the consideration of other memoirs on Eng- 
lish Geology. The limestone which the Germans call muschelkalk, 
and the numerous fossils which are peculiar to it, have not yet been 
detected in England in any part of that great series of beds which in- 
tervene between the lias and the coal. In those parts of Germany 
where it occurs, it divides the beds of red marl and sandstone, which 
occupy that great interval into two divisions, the upper of which is 
called keuper, and the lower bunter sandstein. In the absence of 
the muschelkalk in this country, it has been impossible for us to sep- 
arate our new red sandstone into two well defined masses; but Dr. 
Buckland considers that certain portions of the upper beds in War- 
wickshire and elsewhere may be identified with the keuper by their 
mineral character, and near Warwick by the remains of a Saurian, 
which he believes to be of the genus Phytosaurus, a genus charac- 
teristic of the keuper of Wirtemberg. 
An examination in the South-east of England of the strata usually 
termed plastic clay, has led Mr. John Morris to offer several new, 
and as they appear to me, judicious suggestions in regard to the 
classification of these beds. It is well known that wherever the 
tertiary strata are seen in immediate contact with the chalk, they 
consist of alternations of sand, clay, and pebbles, and in some few 
places a calcareous rock ,—all these varying greatly in their thickness 
and in their order of succession in different places. Mr. Morris 
divides those of Woolwich into two parts, and states that the upper 
is characterized by a mixture of marine and fresh-water shells, the 
fresh-water genera being Cyrena, Neritina, Melanopsis, and Planor- 
is. The lower division contains exclusively marine shells. The 
author refers this intermixture to the influx of a river into the sea, 
in which the London clay was formed. Mr. Morris considers the 
Bognor strata, which rest immediately upon chalk, as the equivalents 
of the lower Woolwich deposit, observing that the shells agree with 
those of the London clay. These remarks seem to confirm the con- 
clusion to which he had been previously led by the grand section at 
Alum Bay in the Isle of Wight, namely that the beds usually styled 
plastic and London clays belong to one zoological period. 
