168 ON BIO-GEOLOGY. [vn. 



only species now found in Devon and Cornwall, 

 marking the New Forest as the extreme eastern limit 

 of the Atlantic flora. We have again the heaths, 

 which, as I have just said, are found neither in 

 America nor in Asia, and must, I believe, have come 

 from some south-western land long since submerged 

 beneath the sea. But more, we have in the New 

 Forest two plants which are members of the South 

 Europe, or properly, the Atlantic flora; which must 

 have come from the south and south-east ; and which 

 are found in no other spots in these islands. I mean 

 the lovely Gladiolus, which grows abundantly under 

 the ferns near Lyndhurst, certainly wild, but it does 

 not approach England elsewhere nearer than the 

 Loire and the Khine ; and next, that delicate orchid, 

 the Spiranthes cestivalis, which is known only in a bog 

 near Lyndhurst and in the Channel Islands, while on the 

 Continent it extends from Southern Europe all through 

 France. Now, what do these two plants mark ? They 

 give us a point in botany, though not in time, to de- 

 termine when the south of England was parted from 

 the opposite shores of France; and whenever that was, 

 it was just after the Gladiolus and Spiranthes got 

 hither. Two little colonies of these lovely flowers 

 arrived just before their retreat was cut off. They 

 found the country already occupied with other plants ; 

 and, not being reinforced by fresh colonists from the 

 south, have not been able to spread farther north than 

 Lyndhurst. Thus, in the New Forest, and, I may say 

 in the Bagshot moors, you find plants which you do 

 not expect, and do not find plants which you do expect; 

 and you are, or ought to be, puzzled, and I hope also 

 interested, and stirred up to find out more. 



