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At Turkey Creek unaltered Cretaceous strata are again well seen, dipping gently E. S. E. Fossils chiefly of the following species are there abundant:

• Ostrea vesicularis,
• Inoceramus Crispii,
• Janira Texana,
• Turrilites (new sp.) and
• Ammonites (new sp.).

April 24.-During the earlier portion of our day's travel horizontal beds of white and light grayish chalky limestone were of constant occurrence. Eight miles from the last encampment the strata again presented evidence of disturbance, and after traveling a short distance farther they were found reposing at an angle of about sixty degrees on a mass of dark basalt, very similar to that encountered upon the Rio Frio and at Fort Inge. This outburst is about a mile wide, and its bearing is northeast and southwest. At its western edge the Cretaceous Limestone is again observed, inclined at an angle of about sixty degrees in a direction opposite to that on the east, and thence it continues to be seen at frequent intervals, often in undulated beds, until we arrive at Fort Clark, where it is again nearly horizontal.

The surface of the country during the latter portion of the day's march was somewhat broken. Small angular fragments of iron ore, the same as noticed yesterday, were again observed frequently strewn over the ground. Soil and sub-soil the same as before.

Distance, 16¼ miles.