420 Editorial Comment. 
an adjoining well, from which 10 tons o£ sheet lead were lately 
taken, was used as a reservoir for the warm water. 
The city of Bath was defended by a line of vast fortified 
camps against the Saxon invaders. Some of these camps prob- 
ably date from times much more ancient even than that period, 
but were re-occupied by the Romano-Britains during the Saxon 
invasion. The great battle of Deorham (577, A. D,), at the 
camp of the same name, was the decisive conflict. The Saxons 
were masters of the field, and the cities of Bath, Cirencester' and 
Gloucester fell into their hands and were sackec" and destroyed. 
From this camp the members of the Association, who visited the 
spot on Saturday, could look over the whole flat country and 
understand the value of these natural fortresses, when strength- 
ened by man. After that date the city was deserted, or nearly 
so, for many years. The mud and silt accumulated in the 
Roman bath to a depth of 10 feet, burying the tank, the col- 
umns and the portecoes, so that they were completely lost to 
view. In one corner was found a wild duck's egg, showing the 
desolation of the once crowded city. Other buildings ultimately 
rose on the ruins, and the bath was almost forgotten. Accident 
revealed it a few years ago, and it now forms, or will form when 
fully excavated, one of the most interesting historic monuments 
of this historic city. 
The Geological Section met on September 6th and proceeded 
at once to business by hearing an address from its president, 
Prof. W. B. Dawkins, of Manchester, on the relative value of 
the evidence drawn from different forms of life in the correla- 
tion of the cenozoic strata. This author, as is well known, has 
long insisted on the special importance of the mammalia for 
this purpose during the tertiary age, and naturally, therefore, 
reverted to this topic, pointing out how their rapid evolution 
supplies a more delicate chronometer than that afforded by the 
slow development of the invertebrata. It gives us, as it were, 
a larger dial plate on which the slow advance of the hand 
can be more readily detected, and, consequently, the intervals 
of time more exactly measured, than in any other way. On 
this principle Prof. Dawkins proceeded to divide the Tertiary 
and Post-tertiary strata (objecting, it should be added, to the 
use of the latter term) into stages marked by the presence or 
absence of certain forms of mammalia, and in this way he out- 
