We present a search for spatial and redshift correlations in a 2 Å resolution spectroscopic survey of the Ly \alpha forest at 2.15 < z < 3.37 toward ten QSOs concentrated within a 1 ^ { \circ } diameter field .
We find a signal at 2.7 \sigma significance for correlations of the Ly \alpha absorption line wavelengths between different lines of sight over the whole redshift range .
The significance rises to 3.2 \sigma if we restrict the redshift range to 2.60 < z < 3.37 , and to 4.0 \sigma if we further restrict the sample to lines with rest equivalent width 0.1 \leq W _ { 0 } / { \AA } < 0.9 .
We conclude that a significant fraction of the Ly \alpha forest arises in structures whose correlation length extends at least over 30 arcmin ( \sim 26 ~ { } h ^ { -1 } comoving Mpc at z = 2.6 for H _ { 0 } \equiv 100 h km s ^ { -1 } Mpc ^ { -1 } , \Omega = 1.0 , \Lambda = 0 ) .
We have also calculated the three dimensional two point correlation function for Ly \alpha absorbers ; we do not detect any significant signal in the data .
However , we note that line blending prevents us from detecting the signal produced by a 100 % overdensity of Ly \alpha absorbers in simulated data .
We find that the Ly \alpha forest redshift distribution provides a more sensitive test for such clustering than the three dimensional two point correlation function .