I used tar to create a tar and gzipped file on Linux. I then FTP'd it to another Linux server, which turned it into two files

file.tar.gz
file.tar.gz.1

I assume the FTP program split it out. I've copied both files to my PC now, and I'd like to reconstitute it. How do I do that? My Google-fu has failed me. Both files can be decompressed individually but there seems to be some duplicates, which is odd.

Alternately I could put it back together on unix then download again, but since it's 4GB I'd rather as I'm near my cap.