EVOLUTIONAL PALZONTOLOGY IN 
RELATION TO THE LOWER 
PALZOZOIC ROCKS. 
ADDRESS TO SECTION C (GEOLOGY) BY 
GERTRUDE L. ELLES, M.B.E., D.Sc., 
PRESIDENT OF THE SECTION. 
Ir is just twenty-seven years since the British Association last met in 
Liverpool, and in casting my mind back over the intervening years 
and thinking how our Science stands to-day with regard to its position 
then, it has appeared to me that one at any rate of the most important 
lines along which progress has been achieved is due to the growth of 
what may be termed the genetic principle. This would seem to be 
equally true both as regards Petrology and Paleontology, for it is 
becoming increasingly evident that conceptions and classifications, 
whether they be of rocks or of fossils, if they are to be natural, must 
be based fundamentally upon origin and descent. Therefore, situated! 
as we are here in Liverpool, almost within sight of the Welsh Hills: 
on the one hand and the Lake District Fells on the other, both classic 
areas so far as the Lower Paleozoic rocks are concerned, it may perhaps: 
be appropriate to see how far this principle may be applied to the eluci- 
dation of problems connected with these Lower Paleozoic rocks, to 
note what has been achieved in this respect, and how much yet remains 
to be done. The subject, therefore, of my address to you to-day is 
‘Evolutional Paleontology in Relation to the Lower Paleozoic Rocks.’ 
Problems of the Older Rocks. 
As I interpret the facts, the chief problems still awaiting solution 
are both fundamentally stratigraphical: on the one hand there are 
problems relating to classification, that is, of subdivisions of the forma- 
tions on a basis that shall be of wide application, and render possible 
correlation of beds in areas far removed from one another; on the 
other, there is the actual structural relationship existing between these 
beds as seen in the field, which, when rightly interpreted, makes 
evident the nature and extent of those deformational strains that have 
from time to time so profoundly affected the rocks of the Earth’s crust. 
With regard to classification, the problems are of different degrees of 
magnitude; there are, for example, those larger difficulties relating 
to the satisfactory determination of the upper and lower limits of the 
formations; there are also those connected with the correlation of all 
those smaller local subdivisions of formations with which Strati- 
graphical Geology is becoming increasingly overburdened without any 
prospect of compensation unless a fresh principle be introduced. 
