I found this online, FWIW:
The THOMAS MASON Goldline is a collection of 2/140 yarn, which is among the finest custom shirtings currently available.
These fabrics are made in the old English way, and quality is paramount. The Goldline range in 2/140 utilizes the finest of long staple Egyptian Giza cottons, which are spun in Switzerland. The closest controls at all levels, and the special finishing methods which have been developed for the qualities, all ensure a fabric which is quite unique in appearance, handle and performance.
The Goldline qualities variously explore the subtleties possible through 2/140 yarn, and the design direction encompasses the timeless elements of refined classicism.
The THOMAS MASON Silverline is a collection of 2/100s yarns with a heavier feel, but the same boldness you have become accustomed to with the Goldline.