Sentence:  Reserve values of the primary Persian Gulf province vary greatly in different parts of the area; thus the northern two-thirds of the British area in Iran, and. a strip 50 miles wide in eastern Iran are <WSD>ultrarich</WSD>, as is the strip in Saudi Arabia, etc., on the west coast of the Persian Gulf from Trucial Oman north. 
Meaning of the word marked with <WSD> tags:  Unusually full of desired resources, abounding.