In the early 1890s a bank was formed with quarters on the ground floor of the Spaulding Block; the building was owned by Titus N. Spaulding, who was married to Katherine Brown Potter's sister, Abbie Brown Spaulding. The bank was a privately owned concern, known as Potter and Co., bankers, run by Mr. and Mrs. Potter [presumably George and Katherine Potter]. It was later sold to the interests which formed the Adirondack National Bank.
From comparison to historic photos, it appears that the Adirondack National Bank was located in the ground-floor storefront on the left as one faced the building from Main Street. The small family business of Potter and Co. Bankers that preceded it likely occupied the same space before the banking business was sold to Alfred L. Donaldson, William Minshull and John F. Neilson, apparently in 1897, when it was said that they founded the first national bank in the Adirondacks.
From the Adirondack Daily Enterprise, February 1, 1955 — an excerpt from a long article:
Second Saranac Lake Landmark to be Razed March 1
The Potter and Co. Bankers, which was purchased and became the Adirondack National Bank, had offices there [in the Spaulding Block]. The bank moved to the Kollecker site, then known as the Coulter Block, and stayed there until it bought the present site across the road on Main Street [in 2012 the location of First Niagara Bank].