You are close about the age of your clock. E. N. Welch Manufacturing Company was taken over by the Sessions' family in 1902 after Welch had financial problems due to two major fires that all but destroyed the plant in 1899.
Your clock is a black mantel clock that was very stylish from the 1880's until the 1920's. The model of yours is called "Manhattan". It was made circa 1921.
If it is all original, it should have an eight-day movement with the hours striking on a cathedral gong and the half-hour on a cup bell mounted on the rear of the movement. It has a decorated Iveroid dial. (a name made up by Sessions meaning a kind of celluloid-paper mix)
It has marbleized moldings and Egyptian columns. The metal moldings are made of cast bronze.
The value in 2002 was listed as $400. This would be what it would bring if sold in an antique store. You would probably get less at auction.
