WORTH NOTING ON TV

* WEDNESDAY

The New Explorers (PBS, 8-9 p.m.): Paul Sereno is a 35-year-old paleontologist whose exploits make it hard to resist comparisons with Indiana Jones. The University of Chicago scientist has already discovered fossils of the most primitive dinosaur, among other finds.

In ``Skeletons in the Sand,'' an episode premiering the fifth season of a monthly series that focuses on scientists, he heads for Africa's Sahara Desert with a group of young scientists. They make a three-month trek across truly tough terrain, arriving at a ``dinosaur graveyard'' in northern Niger, where he hopes to find fossils that will fill in some blanks in the extinct reptile's evolution.

But desert conditions are not the only obstacles the team faces. In Niger, Mr. Sereno discovers that permission to work in the area has been denied. In the end, however, the team makes new finds and returns to Chicago with satisfied smiles and some six tons of bones.

* THURSDAY

Cops (Fox, 9-10 p.m.): The most honest, revealing, and least exploitative of all TV's ``reality'' shows has done episodes all over the United States, as well as in Moscow and London. But one show the series hasn't been able to film is the real ``NYPD Blue,'' as it were: It hasn't been allowed to bring its cameras along on police activities on the streets of New York.

It got there over the summer, spending six weeks making nightly tours with New York officers and capturing enough good footage to prompt Fox to program two half-hour episodes back-to-back on a special night (the regular ``Cops'' broadcast is on Saturdays).

The telecast includes scenes of officers using concussion grenades in a raid on a reported drug house and going after a suspect who may have cut a hole in a roof to break into a store. Other officers survey New York from a helicopter to help fellow cops on foot. Together, these shots offer a sampling of how one of the world's largest and most complex police forces works.

The series expects to include more New York episodes in November.

Please check local listings for these programs.