Trying to find them on the 1851 census, (can see the 1861 census) - they obviously were around Merthyr Tydfil in 1847

Using the GRO INDEX

PUGH, Catherine - mother's maiden surname: JELLAMY

GRO Reference: 1847 M Quarter in Merthyr Tydfil Volume 26 Page 433

PUGH, William James 1849 J Quarter Merthyr Tydfil Volume 26 Pages 489 (mother's maiden name: JELLAMY)