474 
THE GEOLOGIST. 
is more darkly ferruginous and their texture markedly oolitic or 
granular, though not untrequently they change to a deep green hue, 
imparted to them by the protoxide of iron, when the granular structure 
becomes less observable. The fossils, also, which they enclose, though 
exceedingly distinctive and familiar, have not yet been found in situ 
at Hotham. They are the common forms of the true Marlstone — the 
" Spinatus " and " Margaritatus " zone of Oppel and Wright — which is 
shown in typical sections, as at Gretton, near Winchcombe, in Glouces- 
tershire, to occupy the top of the Middle Lias in the southern counties. 
I collected here the large Peden equivalvis and P. corneus, both of 
which were plentiful as usual, Belemnites, Pleuromya unioides (?), 
Cardinia crassissima, and Ammonites Englehardti, with some others. 
Tile drift which I have been now considering contrasts remarkably, 
from its mixed character, with those other and almost homogeneous 
deposits \vhich have been shown to cover the neighbourhood of North 
Cave. 
III. It may be about 200 yards across the Middle Lias ; but its 
junction with the rock next succeeding is not well exhibited. The 
country is now iiat to the foot of the chalk, and the sequence of the 
different rocks that traverse this level is partly undeterminable from 
lack of sections, and partly obscured by drift, so that I could not make 
it out with sufficient exactness. I ascertained, however, that the 
ferruginous beds give place to an inconsiderable band of yellow tenacious 
clay ; and that this again is apparently succeeded by a still narrower 
zone of very peculiar marly Limestone, which I shall call provisionally 
the LiGNiFEEotrs Marl, and describe as fuUy as my present materials 
will permit. I regret that these are not more ample, which is owing, 
in part, to my limited opportunities. I believe this to be an exceptional 
bed, possibly it may even be unknown hitherto, and unrecorded in our 
series. Its lithological character might refer it to the Upper Lias ; 
but its fossils in general, and particularly in one or two instances, are 
much more of Oolitic than Liassic types ; and consequently I should be 
inclined, in the existing state of my knowledge, to assign it an inter- 
mediate place between the Upper Lias and Inferior Oolite, somewhere 
in that " debatable ground " which has lately received such 
elaborate illustration from Dr. Wright. I have reason to suspect the 
existence of the Uj)per Lias Clay at Hotham ; and I shall hope to prove 
that I have seen there the lower portion of the Inferior Oolite, a little 
