List of Dtatomacee found tr Chester and 
District, and Chm Buchan, 2a. 
BY DR. H. STOLTERFOTH, M.A. 
Read December 8rd, 1874. 
5 sa following list formed the groundwork of a Paper read 
before the Society, December 3rd, 1874. A large number 
of Diatomaceous gatherings had then been made in the im- 
mediate neighbourhood of Chester. An Estuary like that of the 
river Dee presents good collecting ground, and the surface-net 
has been used on the Estuary with good results on fine bright 
days. ‘The high elevations in Nerth Wales have also given 
many of the forms peculiar to such habitats, and there are 
abundance of ditches in which fresh-water forms may be found. 
The extensive marshes of Frodsham, Helsby, &c., have yielded 
good specimens. Surfaces of rocks, in which the district 
abounds, subjected to drippings from water, often present the 
well-known olive green, rich in Diatoms, and these have, in 
most cases, been carefully examined. The method of collecting 
and preserving Diatoms has been so often described that I 
need not enter on this subject. 
All the forms mentioned in the following list have been found 
in the district worked by the Chester Society of Natural Science, 
with one exception —that is, the Fossil Diatomacee of the Lake 
Cwm Bychan. I have, however, included this (17) for the 
reason that it is the only fossil bed of Diatoms known in 
N. Wales; and also because this earth was mentioned by 
Wm. Swirx, in his ‘Synopsis of British Diatomacem,” as 
