Nearly sinusoidal microoscillations of air pressure of the order of 1 to 10 microbars (dynes/cm²), which have been recorded on a Lamont tripartite array of line microphones, have been identified as infrasonic waves arising from an intense atmospheric low pressure system off Newfoundland. Although the nearly sinusoidal pressure variations show good coherence among the stations, there is enough wave breakdown among the stations to suggest interference from a widespread source. Other factors indicate this source to be ocean waves. It is concluded that the spectral character of both microbaroms and microseisms is a function of a common generating mechanism, but microbarom amplitude variations depend also on atmospheric conditions along the path.