The picture shows a view of this Old Brunswick Maine Simpson's Animal Park Advertising Souvenir Pin Back Button. The pinback button is not dated but it is old. The park is believed to have closed long ago. The button has a yellow background and black lettering. It is marked as follows:
SIMPSON'S ANIMAL PARK BRUNSWICK MAINE
The pin measures 1-1/4'' wide. It is in near mint condition as pictured with a few very light spots.