"The Ark" by Margot Benary-Isbert

I read The Ark several times as a teen -- our rural North Carolina library had it and the sequel, Rowan Farm.  I still remember they were both bound in that weird orange hardcover binding that library books so often got rebound into when their original covers wore out.
I actually tried to find this book again every now and then as an adult, because I remembered loving it.  But I didn't remember the author's name, or the name of the sequel.  Do you know how hopeless it is to search the internet fo...