Which preposition to use with outliers

of Occurrences 7%

At noon we were only two hundred and ten miles from Sombrero, 'the Spanish Hat,' a lonely island, which is here the first outlier of the New World.

in Occurrences 1%

The physical skeleton of the county may be roughly described as consisting of three parallel ranges of hills running transversely across itthe Mendips and their outliers in the N.E., the insignificant Poldens in the centre, and the Quantocks and Exmoor in the W., with the Blackdowns occupying the S.W. corner.

Which preposition to use with  outliers