It was a shell of a sight. More than 200 sea turtles washed ashore in Cape Cod late last week after being cold-stunned, according to the Massachusetts Audubon Society. Many were frozen solid, with “flippers in all weird positions like they were swimming,” due to unseasonable single-digit temperatures. Experts say stranded turtles — which linger in increasingly warm local waters eating shellfish instead of heading south for winter — aren’t unexpected, but this year has seen unprecedented numbers. The Audubon Society expects to rescue some 1,000 more this year.