In their model for the mid-Cretaceous tectonic evolution of central and northern Alaska, Miller and Hudson <1991> (hereinafter referred to as M-H) suggest that the contractional Jurassic to Cretaceous Brooks Range orogen and rocks in a very broadly defined hinterland collapsed and fragmented due to postcontractional wholesale lithospheric extension; this extension event created the present distribution of continental and oceanic crustal fragments and sedimentary basins. While we acknowledge the existence of a zone of extensional faulting along the southern flank of the Brooks Range, we find much evidence that contradicts the model forwarded by M-H. Our objections center on (1) the constraints on the timing of extensional versus contractional tectonism in the Brooks Range orogen and (2) the evidence for extreme extensional thinning within the broader hinterland of the Brooks Range. We address several of their ''key geologic relations'' (M-H, p. 782) below. We conclude that evidence for extension is restricted to the south flank of the present Brooks Range and that extension was contemporaneous with contractional deformation in the Brooks Range itself. ¿ American Geophysical Union 1993