Claim CD102.1: Out-of-order strata occur at the Lewis Overthrust
Brief response in the Index to Creationist Claims in the TalkOrigins Archive.
Article by John G. Solum in the TalkOrigins Archive. Takes a look at thrust faults and then focuses on the Lewis Overthrust, in response to creationist claims about it.
Geology in Error?: The Lewis Thrust
Article by Joel Hanes in the TalkOrigins Archive.
Wikipedia article. Although this does not deal with creationist claims about the formation, it contains useful information and diagrams showing how it formed; understanding this will help explain why creationist claims about it do not stand up.