IRScNB_P4087_012996P_23_Bulletin 21.pdf
Bulletin of the Royal Belgian Natural History Museum. 1930-1948 / 23 - 1947 Jones, O.T. 1947.
On Silurian Graptolite Shales found below the Chalk Northwest of Liège.
irscnb_p4087_012996p_23_bulletin-21.pdf — PDF document, 296 KB (304052 bytes)