Can anyone identify this model?

[Trail Snail]

I have inherited a sewing machine, and the only marking on it is "Merritt".

What I really want is to get my hands on a user manual, and will need to know the model name / number. Pictures of the machine and serial number are below.

Anyone have any ideas?

 

[Mesquite]

Looks like it's a Singer Merritt model 158