I have been enjoying a visit at your on-line paper money gallery at www.CdnPaperMoney.com. In the $4 Dominion note section, I found a (gasp!) mistake:
"Four dollars was historically significant as it was roughly equal to one
British pound (£).
In fact, the British pound was equivalent to $4.86 2/3, totally unsuitable for use in most of British North America. We had our own home-grown Canadian Pound!
Yes, we did! We called it the Pound Halifax Currency, or just Pound Currency (as opposed to Pound Sterling). It was not founded upon sterling but on the dollar, the Spanish-American dollar to be precise (as was the US dollar), and our Canadian pound was exactly equivalent, by statute, to four dollars, $4.00. Thus the $4 note was the continuation of our pound currency, for years and years after we officially went off the Canadian pounds, Canadian shillings, Canadian pence system in 1858. (Observe that the Canadian shilling = 20¢, thus the 1858 20¢ piece!)
The $4 note enabled the federal government to encroach once again on the chartered bank's preserve of paper money issue so the denomination continued long after our Canadian £-based system was forgotten.
When the federal government gave itself the right to issue $5 notes, the $4's were soon withdrawn. The $5 Dominion notes never were much of a threat to the chartered bank circulation, as the latter kept the lion's share of that denomination in circulation until some time after the Bank of Canada began issuing notes in 1935.
I would say that the Halifax Currency Pound and Sterling Pound is one of the least understood, most often confused subjects in Canadian numismatics.