Mock , 
PREFACE. 
HELLS have been poetically designated the “ Medals of 
Creation.” They occur in rocks of all ages, and every- 
where tell their own story, e.g., in Somerset the huge ammonites 
of the oolite quarries indicate that countless years ago parts of 
the county were covered with a tropical sea in which cephalo- 
pods swarmed. [Existing as well as fossil forms afford valuable 
evidence of a past order of things. The marine shells that 
occur in sandy and pebbly beds far inland on the moors are 
eloquent witnesses to the great alterations of the coast line of 
the county within comparatively recent times. 
The myriads of shells of Helicella barbara (perhaps better 
known under its old name of Helix acuta), which live in the 
hollows of the dunes between Burnham and Berrow, do not 
attract the attention of the majority of pedestrians, but to the 
conchologist they have a special interest. Their presence there 
is to him a link in the chain of evidence that certain elements 
of our existing fauna arrived from the continent by a land 
connection in the south-west, of which the Scilly Isles are 
vestiges. 
As with Helicella barbara, so it is with all the other mol- 
lusea, there is not a single species whose life history is devoid 
of interest in some way or the other. It is stimulating to have 
a hobby, especially if it compels one to 
‘*Go forth under the open sky, and list 
To Nature’s teachings.” 
One of the most delightful of such hobbies is conchology, and 
it is never too late to start upon it. The late Mr. George 
Barlee, of whose fine collection of shells inthe Oxford Museum 
it has been written, “it should be seen by all conchologists, it 
