NATURAL HISTORY OF THE BANKS OF THE TAY. 
49 
Section II.—Across the Tay Valley in neighbourhood of Perth. 
a —a, boulder clay ; b — b, “ accumulative ” river deposits ; c — c, “dispersive” 
river beds of the “great upheaval” valley; d —the estuarine clays of extended 
marine conditions; e — e, “dispersive” river beds of post-estuarine times; /, 
buried site of ancient river. The building in centre of diagram is in the posi¬ 
tion of St. John’s Kirk ; that on the higher terrace indicates the position of 
St. Ninian’s Cathedral. 
Section III.— Across the Tay at “Woody Island,” 
Showing position of the Island upon a higher shelf of the estuarine clays (a — a), 
while the river (bj is denuding the clays at c, and depositing coarse gravels and 
sands upon a lower level at d — d. 
D 
