Gregory, on Fossil Diatomacece. 105 
I have seen E. heptodon. E. serra seems to be confined to 
Scandinavian deposits. 
Although differing from the Mull deposit in regard to the 
forms I have named, and also some others, this Bergmehl 
agrees with it in many points, as in the abundance of Navicula 
rhomhoides and N. serians, that of many Pimiularice, of Gompho- 
nema coronatum, of several Cymhellw, Stauroneides, Tahellarice, 
OrthosircB, and other forms, but especially in the presence of 
Eunotia incisa, first observed by me in the Mull earth. The 
variety /6 is here the more frequent. 
There is another form, common to these two deposits, 
which, so far as I know, has not been described. It is an 
aspect like a Synedra, long and narrow, straight in the middle, 
and having the ends curved opposite ways, which gives to it 
a sigmoid character. I am inclined, however, to suppose it 
to be a Nitzschia, for while I cannot make out the transverse 
striae of Synedra^ I can see a row of puncta on each margin 
in some specimens. It is, however, quite distinct from 
N, sigmoidea. In the Mull earth it is generally broken, so that 
we see only one-half ; but I have found several entire ex- 
amples. In the Lapland deposit it is more frequent, and 
often entire, although from its slender proportions it is apt to 
be broken, and fragments also occur. As we have already 
Nitzschia sigmoidea and N. sigma, this form, if it be a 
Nitzschia, may be called N. sigynatella. 
I have still to notice a form occurring in this Lapland Berg- 
mehl, which, so far as I have been able to ascertain, is un- 
described. It is narrow and of considerable length, but bent 
into the form of a sickle, or nearly a semicircle. It is slightly 
attenuated at the rather acute apices, and has very strong and 
distinct, though rather fine, transverse striae. It approaches 
more nearly to Eunotia arcits, as figured by Smith, but differs 
entirely from it, in being much more curved, in the absence 
of the characteristic prominence in the so-called ventral 
surface, and in its having much stronger and more distinct 
striae, all of which characters combined give it an entirely 
peculiar aspect. Taking it, for the present, to be a Eunotia, 
I propose for it the name of Eunotia falx, or E. falcata. 
I would now direct attention to a deposit, of which speci- 
mens were sent to me by Mr. Norman, under the name of 
Liineburg. It is well known that there is an extensive de- 
posit on the Liineburg heath, in Hanover, and one part of it 
is known as the earth or Bergmehl of Oberrohe, near Liine- 
burg, another as that of the Liineburg heath. These I find to 
be quite distinct from the deposit of which I now speak, as 
obtained from Mr. Norman ; for this, as I have found, has a 
