This paper presents the results of a study of solar extreme ultraviolet radiation in the range 200--400 ¿ mae looking through the arth's upper atmosphere by the Oso 7 satellite. The results of special interest in this work were those mad when the attenuation in the atmosphere occurred in the 250- to 500-km altitude range. Using published molecular absorption cross sections at 304 and 256 ¿ (Huffman, 1969; Hinteregger and Hall, 1969), we were able to demonstrate that the sunset data were consistent with the Jacchia (1971) atmosphere model for a mean exopheric temperature of 1050¿50 K over the altitude range observed. However, the sunrise measurements above 330 km cannot fit by this model for any single temperature and if correct may give evidence for dynamic phenomena taking place in these upper layers while they are being heated. Utilizing the atmospheric model fitted to sunset data at 304 and 256 ¿, we were able to derive values of 6.3¿0.6 Mb (10-8 cm2) and 6.9¿3.0 Mb for the cross sections of O and N2, respectively, at 284 ¿ and 7.6¿0.8 Mb and 4.8¿3.9 Mb for the respective cross sections at 335 ¿.