82 GOSSIP ON ANTIQUITT OF MAN. 



tertiary periods. One of these belongs to the older pliocene, and 

 is divisible into the coralline and the red crag — the coralline being 

 the older of the two. The other belongs to the newer pliocene, 

 more advanced in time as the term indicates, and is commonly 

 called the Norwich, and sometimes the mammaliferous crag. I 

 need not go into a lengthy and particular description of these 

 formations, any one who desires that will find it in Sir Charles 

 Lyell's "Antiquity of Man," and other works on Geology. It will 

 suffice to state, that in them are a number of shells of recent 

 species, the proportion of the recent to the extinct being greater 

 in the newer beds. Thus, in the coralline or oldest crag, there is 

 found fifty-one per cent of recent, in the red crag fifty-seven, and 

 in the Norwich crag eighty-seven. These shells prove a progres- 

 sive change in the climate. That of the coralline must have been 

 warm, for twenty-seven southern shells are found, of species which 

 now inhabit the Mediterranean and West Indies, and but two 

 closely related to arctic fauna. Only thu'teen of these southern 

 shells occur in the red crag, together with three new southern 

 species, but eight northern species are found, showing that the 

 climate was less fitted to support some of the testacea that lived in 

 the previous period, and becoming more suitable for the northern 

 species. All the foregoing southern species disappear from the 

 Norwich crag, but all the eight northern species remain, and four 

 arctic shells are added. Thus is represented the increasing cold, 

 the gradual approach to the glacial period of depression, although, 

 in the time of the Norwich crag, probably there was no season in 

 which the cold was intense. 



Connected with the marine deposit of the Norwich crag, at a 

 place called Cromer Jetty, where it thins out, is a submerged forest, 

 which has been traced for more than forty miles, and which at one 

 time must have had a considerable elevation above the sea. The 

 Scotch fir, spruce fir, yew, alder and oak, are among the trees that 

 are known to have grown in that region, and various extinct mam- 

 malia flourished there, of which numerous bones have been col- 

 lected. 



There is no doubt about the age of these respective formations. 

 They belong most certainly to the older and newer pliocene strata, 

 and the associated fauna are those Avhich previously and probably 



