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Thanks Jim,  When I said drop that was page rank as I have been tracking through Google Search Console search analytics.  We have an adaptive site that detects the users equipment.  I URLs are the same in both environments.    When I look at desktop the average page rank dropped 4 positions taking us off the front page while the average position on mobile dropped a half a position.  Does that help?  Thanks

Thank You Chris

Thanks for the answer Kevin. For those interested in learning about using the HTTP Header to establish a canonical tag, you can look here on Google's Webmaster Central Blog.

Thank you for your responses!

Hi, Google's advice on this configuration is to use the "Vary HTTP header" to let the Google bot know that the same url is used for mobile/desktop. See also: https://developers.google.com/webmasters/mobile-sites/mobile-seo/configurations/dynamic-serving?hl=en . While Google strongly recommends responsive design - this option is also valid. Matt Cuts says the same in this video: https://www.youtube.com/watch?v=va6qtaiZRHg (it starts with all the caching stuff, the part which might be of interest to you starts at 3:38) Hope this clarifies, Dirk

I would be curious to look at each form of the pages using the LDA tool. The main reason to use the tool is to understand if you are significantly reducing the page's relevancy to your target keyword(s).