PROCEEDINGS—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. xli 
WINTER SESSION, 1899-1900. 
9th November, 1899. 
Henry Coates, F.R.S.E., President, in the Chair. 
Mr. Alex. M. Rodger, as Delegate of the Society to the British 
Association for the Advancement of Science, gave a report of the 
Meetings of the Association at Dover. 
He also, as Delegate to the Museums’ Association, gave a report 
of the Meetings of that Association at Brighton. 
The President delivered the following Opening Address :— 
Ladies and Gentlemen, —At the beginning of the winter session 
it has been our custom to review, very briefly, the work of the Society 
during the preceding summer, and to record any outstanding features 
of the season that may have affected animal and plant life in our 
district, or any features of inorganic nature that may have been 
brought to light. 
geological notes. 
To take the last of these heads first, I may refer to the strata of 
superficial deposits which have been revealed in the deep cutting 
recently made across the North Inch and along Tay Street for the 
purpose of laying a new culvert. These are of interest as throwing 
some light on the conditions which have obtained in this part of the 
Tay Valley since early post-glacial times. Across the North Inch, 
where the cutting was about twelve feet deep, the deposit consists 
almost entirely of finely bedded sand and silt, evidently of river 
origin, and laid down without much disturbance. Intercalated with 
these are occasional beds of fine river-worn gravel. In Tay Street, 
where the cutting was rather deeper, a larger proportion of argilla¬ 
ceous material was revealed, the clay being mingled with the sand 
and silt. The conclusions which these conditions indicated were 
that for a very long period the ground now occupied by the North 
Inch has been a growing “ Haughland,” gradually being built up by 
layers of fine sediment spread upon its surface by the river when in 
flood, and that, in the lower reach, estuarine conditions were begin¬ 
ning to make themselves felt. 
This reference to the deposition of sediment by the river suggests 
a subject of enquiry which was referred to by Sir Archibald Geikie 
in his recent address to the Geological Section of the British Asso¬ 
ciation. His chief topic was the age of the earth, and he pointed 
out how impossible it was to estimate the time necessary for the 
building up of any particular series of sedimentary rocks without 
careful and prolonged experimental investigation, carried on simul¬ 
taneously by a number of observers in different parts of the country, 
for the purpose of recording the rate at which a given area was 
being denuded, or at which a given deposit was being built up. 
D 
