* Chevron Corp. said its third-quarter earnings...

* Chevron Corp. said its third-quarter earnings were down 10% from the period a year before. It said the drop reflected higher federal taxes.

The company put earnings for the quarter ended Sept. 30 at $420 million, or $1.29 a share--down $467 million, or $1.37 a share, from the third quarter of 1992.

Special charges mainly related to increases in U.S. corporate income taxes reduced third-quarter earnings $145 million, the San Francisco-based company said. The 1992 third quarter benefited $57 million from special items.

Total revenues were $9.2 billion, down from $10.3 billion in last year’s third quarter.

Excluding the special items in both third quarters, earnings were up 38% from a year earlier.

“Continued declines in operating and administrative expenses, coupled with improved worldwide refined product sales margins and higher U.S. natural gas prices, contributed to our stronger earnings,” Chairman Ken Derr said.