BANK OF MONTREAL 1955 oil gas Dowell vintage ad

Original vintage oil and gas magazine ad, BANK OF MONTREAL  Canadian Oil "Sleuthing" Needs Expert Assistance.  B of M Bank of Montreal, Calgary, 140 Eight Avenue West, Calgary.  

On the reverse side (see Additional Images tab) is  Dowell Sandfrac, Services For The Oil Industry.  Sandfrac equipment in the oil field.  A service subsidiary of the Dow Chemical Company.   Old 1955 petroleum industry advertisement.

approximate size  9  x 12 inches.