ULTRADEEP X-RAY SPECTROSCOPY OF THE CIRCUMGALACTIC MEDIUM AND LOCAL IGMTHE XMM-NEWTON ARCHIVE CONTAINS SEVERAL SPECTROSCOPIC DATASETS ON BRIGHT EXTRAGALACTIC CONTINUUM SOURCES OBTAINED WITH THE REFLECTION GRATING SPECTROMETER THAT REACH CUMULATIVE EXPOSURES TIMES OF ORDER 1.5MSEC. THIS IS MUCH MORE EXPOSURE THAN WAS AVAILABLE THE LAST TIME THESE DATA WERE ANALYZED MORE THAN SEVEN YEARS AGO. THE SPECTRA OF MKN 421 PKS2155-304 AND 3C273 EARLY ON SHOWED CLEAR EVIDENCE FOR ABSORPTION BY PREVIOUSLY UNKNOWN HIGHLY IONIZED GAS ASSOCIATED WITH OUR GALAXY AND/OR THE LOCAL GROUP(HE- AND H-LIKE OXYGEN RESONANCE ABSORPTION LINES AT ZERO REDSHIFT). THE PROPERTIES OF THE ABSORBING MEDIUM (SUCH AS ITS TOTAL MASS AND ITS RELATION TO THE GENERAL 'ECOLOGY' OF THE GALAXY) ARE STILL SUBJECT TO CONSIDERABLE UNCERTAINTY AND DEBATE. I PROPOSE TO ANALYZETHE DEEPEST SPECTRA IN THE XMM-NEWTON ARCHIVE WITH THE AIM OF REACHING THE SENSITIVITY TO DETECT IRON M- AND/OR L-SHELL ABSORPTION WHICH IS A SENSITIVE INDICATOR OF THE IONIZATION BALANCE. SINCE MKN 421 AND PKS2155-304 ARE ROUTINELY OBSERVED AT LEAST ONCE A YEAR FOR CALIBRATION PURPOSES THE CUMULATIVE EXPOSURE TIME ON BOTH SOURCES NOW EXCEEDS NEARLY 1.5MSEC EACH. AND IN FACT PRELIMINARYEXAMINATION OF A SUBSET OF THE DATA SHOWS (SURPRISING AND UNEXPECTED) EVIDENCE FOR ABSORPTION BY (ARGON-LIKE) FE IX.