66 BEITISH MOSSES. 



well-defined British species of the present day. If we take 

 Mr. Wallace's chronology, and hold that 80,000 years have 

 passed since the Glacial epoch disappeared, and 200,000 

 years since the Glacial epoch was at its maximum, we may 

 perhaps give from 100,000 to 150,000 years for the age of 

 this little collection. Out of the eleven Mosses discovered, 

 seven belong to the genus Hypnum, or the family 

 Hypnaceae. This collection, then, is evidence, so far as it 

 goes, (1) that the existing Moss flora is as old as the inter- 

 glacial epoch ; (2) that the Hypnacese were as dominant 

 then as now ; and (3) that the specific forms have remained 

 constant since that epoch. 



Another collection of fourteen Mosses has been dis- 

 covered in a drift in the Clyde valley above the Boulder 

 drift, and tends to confirm the previous conclusions ; as all 

 the species are existing, all now inhabit the valley of the 

 Clyde, and the Hypnaceae are still predominant, though 

 not in so great a proportion as in the Renfrewshire bed. 



A third collection has been found at Hoxne, in Suffolk, 

 in a lacustrine deposit, probably resting in a hollow in the 

 boulder clay. Together with phanerogams of an arctic habit, 

 have been found the remains of ten Mosses, which are 

 described by Mr. Mitten as looking "like a lot of bits 

 drifted down a mountain stream." They are all still 

 dwellers in our island, and exhibit, like the other collec- 

 tions, a preponderance of the family of Hypnaceae. 



But we can give some evidence of more ancient date. 

 Heer inferred the existence of the Mosses in the Liassic 

 period from the presence of remains of a group of small 

 Coleoptera,the existing members of which now live amongst 



