Contrary to what we always thought it would appear that the original design for the Eaton's College Street store only went to Hayter Street (see montage by Wyliespoon below). There was, however an east-west street called Buchanan which was closed to build the store, as can be seen in the Goad 1910 map:
If the full proposal had been built:
As a side note, it's interesting to see on the map the original location of Bishop Strachan School at College and Bay, prior to its relocation to Forest Hill.
On the right: