We shall try to answer as best as we can. Tuttle was taken over by the Michael Kane brick co about 1940. I would not be surprised if Kane continued to make brick at the Tuttle Plants until even Kane closed it operations. That is conjecture on my part, but other manufacturers often did that. see: THIS LINK With respect to the Sullivan brick, it is one I'm not familiar with. It would be helpful to know, where in general, (city/state) you believe these were originally used or found,... also if they are a building brick or firebrick or paver. A photo may be helpful for this.... and us too. Thank you - Fred.
I also found some Sullivan bricks in the back of my lot while putting up a new shed. I also would like to know about them. Are they worth any money?