The school was staffed then - and now - by the Sisters of St. Joseph. In 1959 the faculty consisted of all nuns. The first lay teacher joined the faculty in 1961.
"We've been privileged to be here all 50 years," said Dalton, a member of the religious order.
Dalton has been principal of the school 23 years, although another person has been there even longer.
Karlene Gonyeau attended St. Mary's as a student and has taught at the school the past 23 years. That's 31 years at the school.
"Most of my life I've been part of St. Mary's," Gonyeau said. "I feel very proud to have been able to impart the Gospel of Jesus through the curriculum and spread the good news."
St. Mary's teaches faith, values and character, Gonyeau said, though she's quick to point out St. Mary's graduates are also well-prepared academically and excel as they go on to high school and college.
"The children leave St. Mary's with a very strong education," she said. "Overall, I feel the transition from St. Mary's to high school is a good one for our students."
St. Mary's School has changed a lot during the decades, Gonyeau said, but the core principles remain the same.
"It's been exciting to see the changes, all the new technology like computers and smart boards," she said. "But it's our faith, families and friends who make our school. I feel very blessed to be part of it. When I'm at St. Mary's I feel like I'm home."
Megan Jebb is St. Mary's newest teacher, arriving just this academic year. Like Gonyeau, she is also a St. Mary's graduate.
"As a student I loved St. Mary's," Jebb said, "but as a teacher I have a new appreciation for it. It's a spiritual place; you can actually feel the love. It's like a family."