946 PROFESSOR J. PRESTWICK ON THE EVIDENCES OF A SUBMERGENCE 
size or shape, so as to present an appearance as tumultuous and confused as that of a 
coarse volcanic ao’o-lomerate.” 
This description might be applied almost word for word, to the “ head ” over the 
Raised Beaches of Brighton and Devon. There is the same absence of wear and the 
same local character of the component fragments; the same various degrees of 
coarseness and occasional inclusion of massive blocks ; and the same occasional dip or 
appearance of bedding : to which may be added the same general rarity of organic 
remains. Bones, however, have been met with, though very rarely, but when that is 
the case the authors assign it to a later period. But even at Brighton the greater 
part of the Elephant-bed is unfossiliferous, and it is only occasionally that bones are 
found, whilst in Devon,''' owing to various causes, they are almost unknown. In the 
fissure breccia likewise there are large portions (probably the largest) in which no 
bones are found. The jjresence or not pf bones cannot therefore be considered a 
character of any fixed value, and alone is insufficient as a test of comparative age. 
Messrs. Ramsay and Jas. Geikie state, that the bone breccia of Rosia Bay occupies 
a “ vertical fissure of erosion in the unfossiliferous limestone-agglomerate” and hence 
that the latter must be of older date. But Major Imrie,! who was there when the 
first excavations were going on, says, that it was a cave (with the ordinary cave bone- 
bi'eccia) that had been “ filled up with the concretion ” (agglomerate), and Mr. Smith 
merely says that it was a fissure in the face of the cliff. Unfortunately no sections 
are given to assist us in our conclusions. If this breccia (the older agglomerate) 
were, hoAvever, older than the Raised Beaches, we should expect to find portions of 
it under some of those beaches, but none such are recorded. On the contrary, a 
section given by the authors shows an agglomerate or breccia overlying a beach (see 
fig. 17). They explain this section by supposing this agglomerate (their No. 5) to 
be of later date than the agglomerate or breccia of Rosia and Buena Vista on the 
wmst side of the Rock, but the evidence of superposition is wmnting, and it is difficult 
to suppose that the breccias on the east and west side of the Rock, shown in the twm 
sections in fig. 14, a,re otherwdse than contemporaneous. 
The authors themselves say “ there is no perfectly conclusive evidence to show that 
any of them (the agglomerates) are older than the marine platforms at Europa and 
low'er levels,” and again, “ the agglomerates (No. 5) now referred to (those resting on 
marine deposits, or Raised Beaches, and eroded platforms on the east side of the Rock), 
are similar in most respects to the older accumulations (No. l) in Buena Vista. Like 
them they are made up of angular fragments of limestone of all sizes up to blocks 
several yards in diameter, set in an earthy matrix which is either red or grey.” 
Another section| (fig. 1.5) is described by them at p. 527, fig. 10. They consider 
* I am not aware of any except tlie tootE of Horse, wliicli I found at Hope’s Nose, as mentioned in my 
first paper to the Geological Society. 
t ‘ Trans. Roy. Soc. Edinb.,’ vol. 4, p. 191 ; 1779. 
t This is described somewhat more fully by Professor J. Geikie in ‘ Prehistoric Europe,’ p, 326. 
