24 
corresponds so exactly with the description given by Diodorus (5.22) 
of the island Iktis, to which tin was brought from the mainland 
to be shipped to Graul, that it has been generally considered as the 
place designated by the Greek historian. To this identification it 
has been objected, that the channel between St. Michael’s Moimt 
and the mainland contains the remains of an ancient forest, 
which cannot have grown on land which the sea oveifi-owed. It 
became important therefore to ascertain the age of this forest. Mr. 
Pengelly’s researches and reasonings lead to the conclusion, 
that its growth and submersion belong altogether to pre-historic 
times. The only ground for supposing that the Isle of Wight 
(Yectis) was the Iktis of Diodorus is the similarity of the names ; 
but the width and depth of the Solent Sea are inconsistent with his 
description of Iktis. The tin must have been raised in the neigh¬ 
bourhood of the Land’s End, whence the voyage to the N. W. coast 
of Gaul is shorter than to the Isle of Wight. 
Mr. J. E. Walker then read a paper ‘‘ on the relative ages of 
some of the Lower Cretaceous beds.” He remarked that the Upper 
Greensand and Gault are generally regarded as intimately 
connected, these beds being unconformable with the Lower Green¬ 
sand. The Weald an may have been contemporaneous with some 
part of the Lower Greensand, forming the land bordering the 
Neocomian sea and gradually overflowed by it. 
When a Cretaceous deposit intervenes between the gault and 
the chalk there is no difficulty in determining its place in the series, 
but when it rests on one of the oohtic cla 3 "s its geological position 
is by no means certain. Thus the Earringdon beds have been 
placed in all positions, from above the white chalk to below the 
Lower Greensand. Many of the fossils found in this bed have been 
identified by Mr. Sharpe with species occmuing on the continent in 
beds supposed to be of Upper Greensand age, but Mr. Walker in¬ 
dicated that the most characteristic fossils of the English Upper 
Greensand are wanting at Earringdon and that many of the common 
fossils of that locality are of truly Neocomian type, wliilst the pre¬ 
cise equivalence of the supposed Upper Greensand beds referred to 
by Mr. Sharpe is by no means certain. The deposits at Potton and 
Upware, described by Mr. Walker in former communications, con¬ 
tain fossils identical with those of Earringdon; and even the de¬ 
rived fossils, although less abundant at Earringdon, are of the 
same nature in the three localities. Hence the author concludes 
