The SSA says that 12 baby girls were named Thurley that year, though the SSDI tells me the number could in fact be 31, or higher.
Why the Thurley spike?
A book called Thurley Ruxton, written by Philip Verrill Mighels, was published in 1911. The story was also serialized in several newspapers. Here’s how a reviewer at LibriVox describes it:
This is a rags to riches romance about an exceedingly beautiful, poor, young girl (Thurley Ruxton) who is mentored by one of New York’s elite hostesses. In order to draw them into her social circle, she allows all the famous and moneyed populous of Gotham to believe that Thurley is the princess Thurvinia hiding in New York to escape an arranged marriage.
I haven’t yet managed to find anyone named Thurvinia, though I did discover a Thurley Ruxton Matthews Zabor (1912-2009) in Ohio. Her obituary states that she was “named for the title character in a contemporary novel, “Thurley Ruxton.””