Marine movements were in high demand by the 1850s as boat and rail traffic increased. The marine movement is a specific type that does not have a pendulum. Pendulum clocks do not work on a ship or train because they require a stable base. A marine clock has either a balance wheel or lever escapement and were the perfect choice at sea.
This is an E. N. Welch 30-hour marine clock.
Many makers including E.N Welch would buy ready made movements from other shops, assemble them and sell the finished product under their name.
A short history of E. N. Welch. The E. N Welch company was formed on July 6, 1864. Elisha N. Welch (1809 to 1887) had been making clocks at a factory site on East Main Street at Forestville, Conn. since taking over the bankrupt business of J. C. Brown in or about 1856.

The Welch firm was well known for its handsome rosewood cases, though in 1885, with changing styles in furniture, the surviving firm began to introduce new models with solid walnut cases and discontinued some of the older rosewood veneered cases.

After the death of Elisha Welch in 1887, the firm steadily declined, selling off some of its assets and issuing new stock to raise much needed capital. In May of that year the factory was closed down and a receiver was appointed. The receiver spent nearly two years selling off stock and settling the debts of the firm. It was not until 1896 that the firm resumed production.
But the company continued to struggle, would not survive and in 1902 its assets were bought by the Sessions Clock Co.
This movement was not made by E. N. Welch but was sourced from Laporte Hubbell. There were many variations of this movement but the basic two plate layout was identical. In this particular movement the minute wheel is in the two o’clock position and there is the addition of a seconds arbour running off the second wheel just above the “maker’s” stamp. From 1857 to 1863 the E. N. Welch Co. used this 2-plate, 30 hour marine movement. The exact year? Certainly no later than 1863. (source, NAWCC Watch & Clock bulletin, Nov-Dec 2013)
Otherwise, the case is in good condition with two small veneer chips, the brass bezel is very dirty, almost black from years of grime, the dial has minor losses and the movement is running well at this point though at its fastest speed it is running slow.
The plan is to service the movement, and refresh the case. It should be a fun little project.