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NOTES ON ESSEX GEOLOGY. 
Neptunia contraria below (at Beaumont and Walton-on-Naze), 
the two being also named as the Oakley Horizon and the 
Walton Horizon, a generosity of nomenclature that is hardly to 
be recommended. 
A list of the mollusca “ most characteristic of the Walton 
Crag ” is given, with 66 entries, and it is followed by another 
list “ of northern or recent species . . absent or rare at 
Walton,” with 28 entries. This seems to be an important 
point, and it is one that does not always occur to the compilers 
of lists of fossils. 
The richness of the Red Crag in fossils is well illustrated by 
the work done by Harmer at Beaumont. Many years ago John 
Brown, of Stanway, one of the old Essex geologists, got about 
100 species of mollusca there, from a pit that was closed years 
ago ; but was luckily re-opened in time to absorb some of the 
abundant Crag-hunting industry of the author, who succeeded 
in finding more than 260 species, including with very few 
exceptions, those listed as characteristic of the Walton Crag ; 
but also including a few northern shells which are absent or rare 
at Walton. 
At a new opening which he made at the south-western end 
of the Beaumont outlier Harmer got several species that were 
not found at the old pit, at the south-eastern end of the outlier, 
but which “ are all characteristic of the still newer deposit at 
Little Oakley.” 
Five sections in the Little Oakley outlier are marked on 
Harmer’s map, but apparently from one only, near Poulton Hall, 
did he collect, making up, however, for this by fairly exhaustive 
work. He says :—“ As the Crag of Little Oakley appeared 
to be different in age from anything previously known, I de¬ 
termined to work it out as thoroughly as I could,” and when 
such work has been done by Harmer there can’t be much left 
for any one else to do. 
He succeeded in getting “ more than 350 species and well 
marked varieties of fossils, some of them new to science, and 
many of them known to Wood from the Coralline Crag only. 
The presence of so large a number of distinct forms in one 
seam, little more than 12 inches thick, and only 10 yards long, 
constitutes a striking illustration of the extraordinary richness 
of the molluscan fauna of the North Sea at that period.” This 
