Just north of Mt. Kenya, in the center of this country, modern civilization gradually ggives way to remnants of the Kenya that existed before the coming of the white man.

At Marsabit, one of the more remote outposts of this other Kenya, few residents have ever seen a paved road, used a knife or fork, watched television or tasted piped water. The town residents wear Western clothing, but the herders outside Marsabit still wear a bright red, skirt-like garment, color their hair with ochre and carry spears as they tend their cows.

This journey into the African past is only about 300 miles from Nairobi, Kenya's capital. Few tourists undertake it because the last half of the trip -- unless by plane -- is a dusty trek over a bone-jarring dirt road through a wilderness almost devoid of villages. Yet Marsabit, a town of perhaps 10,000, is one of the most fascinating places in Kenya.

Marsabit is a tribal melting pot, and some of its tribes are related to those of southern Ethiopia. There are the Boran, whose men are distinguished by wavy black hair; the Gabra, a nomadic people who wander between Ethiopia and northern Kenya, living off the blood and milk of their cattle; the Samburu, also a nomadic people whose home base is farther south, and the Turkana, who have filtered in from the region of Lake Turkana (formerly Lake Rudolf) to the west.

Why these diverse peoples have been drawn to Marsabit is no mystery. It is a peculiar sort of oasis, a climatic curiosity in a semi-desert. All around it are low thorn bushes growing out of a sun-baked soil. Occasionally a long-necked gerenuk antelope, or a tiny dikdik bounds through the bush. A few nomads appear with their camels, but for most men and beasts it is not hospitable territory.

Suddenly, however, the road rises out of this bleak but beautiful landscape to the refreshingly cool green mountain on which Marsabit is built. The mountain has its own rainy season, in January and February, while the wilderness around it remains dry. Each morning year-round, one awakens to find the mountain enveloped in a soft mist that gradually gives way to bright sunshine.

The mountain is a national game reserve, and it is one of the few places in Kenya where one can still see the greater kudu, the most majestic of the antelopes. Ernest Hemingway devoted most of his "Green Hills of Africa" to an account of a kudu hunt.

The reserve also boasts the largest elephants in Kenya, and many of them have mammoth tusks. It is believed that the size of the elephants and their tusks is due to the food supply grown in the rich mountain soil.

Most visitors are attracted by the game reserve. Accommodation is limited to a single lodge and a campsite beside a shallow crater lake in the reserve and another campsite just outside the main gate. But there is more to Marsabit than the reserve. Guides can show you what a tourist ordinarily might overlook.

Ahmed, a 19-year-old Boran tribesman, starts his tour with a visit to a Boran village just outside Marsabit. "You can take all the pictures you want," he advises beforehand, "but you must pay the chief."

The Boran huts are unlike the usual, conical-roofed grass huts built by most African tribesmen. They are built in the shape of an inverted bowl. Inside, the beds consist of a floor of hides, raised on stilts about two feet off the ground, and covered on three sides by more hides. Just outside the door are smaller versions of the same thing, used to protect calves and goat kids from predators at night.

"There are many lions around here. I have killed two myself, with my spear," the chief says.

The chief is a handsome man of about 35. He is the only person in the village who speaks English, and his command of the language is good. He never attended school, but learned English while working with a white hunter for three years.

In the center of the village is the boma, an area fenced off by thorny branches that serves as a cattle corral. In the middle of the boam is a rude grave, built of piled stones.

"This is the grave of the mother of the former chief," the new chief explains. "She was 95 when she died."

Being buried in the middle of a cattle pen might not be to everyone's taste. But among the Boran, whose cattle are their wealth, it is a sign of veneration. "Now you can take pictures," the chief says. "But you must pay." He suggests 200 shillings ($27.50). We compromise at 30 shillings ($4.10), and the chief is happy.

When the picture-taking is completed, Ahmed says, "Now we will visit the singing wells."

The name evokes images of some cheap tourist trap, and seems wholly incongruous with this setting. But we start out on a 10-mile drive to the singing wells. There is no road, just a cattle trail. From time to time the car tilts on the uneven surface and seems perilously close to tipping over.

At the end of the trail is a scene out of the Bible. One group of primitive Boran tribesmen graze their hump-backed African cattle on the steep slopes of a hill while, below, others are watering their stock at a long, mud-walled trough.

We scramble down the hill and suddenly hear a chorus of men's voices coming from somewhere below the trough. Eventually we see them -- seven men gathered around a well. With leather buckets, they draw water from the well and toss it into a mud-walled reservoir at a higher level. There, six more men repeat the process, scooping out water with their leather buckets and tossing it up to the cattle trough.

As they work, the men sing a chant which goes something like this: This is for my brown cow And this is for my black-and-white cow And this is for my cow with the crooked horn.

In such fashion, the men "count" their cattle. When they have enumerated their herds, they make way for another bucket brigade, which does the same thing.

The last stop on Ahmed's tour is an immense, ancient crater just outside the reserve. It is about 2,000 feet deep and a half-mile across; when the mountain blew its top, millions of years ago, it must have been a tremendous eruption.

In the center of the crater floor is a Samburu village. There is no water on the crater floor, and the Samburu have to haul it from nearly a mile away scrambling up and donw an elephant path along the steep crater wall.

It seems odd at first sight that any people should want to live in such a remote spot and submit to such hardships. But there is a wealth of green grass in the crater -- good pasturage for the cattle and, perhaps, a sufficient reason for the Samburu to make it their home.