Open one of the two catalogs. From the File menu select "Import from Another Catalog" and select the other catalogs. There are many options there so take your time to read and understand what they will do. You will now have a catalog that is the merge of the two.
PS looking at your screenshots the top screenshots appear to show a folder hierarchy. That's not a catalog but simply the folder structure with your originals in it. The second screenshot appears to show three different catalog files and another folder probably with images in it.
I question if you really do have multiple (different) catalogs, or just "Upgrades" of the SAME catalog.
"My New Catalog X.LRCAT" looks like an original (LR5 ?)
"My New Catalog X-2.LRCAT" looks like the LR5 catalog upgraded to LR-CC version.
"My New Catalog X-2-2.LRCAT" I am not sure about!!! maybe you opened and upgraded the LR5 version a second time in LR-CC.
If you have done different new work in each catalog then a merge by "Import from another Catalog" is one way to keep the new edits.
Thank you for your consideration of my question and your replies. I have created a new master catalog and have imported the catalogs. I appreciate your comments about the Folders hierarchy.
I have now two followup questions - if this is not allowed, I'll pose them as new forum questions.
1- If the new catalog looks good, how does one delete the old ones?
2- Do you have a reference/tutorial on how to end up with one main folder of photos containing the sub-folder hierarchy such as I show in the top Screen Shot example in my original question?
>1- If the new catalog looks good, how does one delete the old ones?
Simply drag them into the trash
>2- Do you have a reference/tutorial on how to end up with one main folder of photos containing the sub-folder hierarchy such as I show in the top Screen Shot example in my original question?
Make sure you pay attention to the import dialog and route the images into that hierarchy. As for moving them after the fact, check the tutorials here: Lightroom tutorials | Learn how to use Photoshop Lightroom and especially the section on importing. Also the tutorials here: Getting Started with Adobe Photoshop Lightroom 5 | Adobe TV especially the organizing section (as well as the importing one) might be helpful. You can move folders around inside Lightroom which will move them outside of it too.
Thank you kindly for your consideration of my Lightroom CC 2015 merge question.
You are correct in that one Catalog was an upgrade.
I had had two separate catalogs in chronological order - each with unique names - each one on a separate external HD.
My Screen Shots above showed the result of importing the earlier one into the second, later catalog onto a larger external HD to hold both with images with room to grow.
I have follow up questions above in answer to another forum member who responded. If you can offer an answer, I'd be very appreciative. Sometimes even with the better tutorials we have these days, we can end up with more finishing steps to complete a task than are shown in tutorials and books.
There is always something to learn.