The correct spelling for the phrase "was trail of" is actually "was a trail of." The sound /ə/ represented by the letter "a" in the middle of the phrase is called a schwa, a weak vowel sound that can be difficult to identify in spoken English. In IPA transcription, the phrase would be /wɑz ə treɪl əv/. Proper spelling is important in written English to avoid confusion and ensure clear communication.