The twelve square miles of earth which were bound together on March 20, 1857, by the Legislature of the State of New Jersey, to form a body politic, thenceforth to be known as the Township of Millburn, is a fractional part of the County of Essex, and a still smaller fragment of the State which gave it birth, but the political entity which came into being just a little more than a hundred years ago, was founded in a region many times a million years old, whose geological processes were important enough for scientists to have given to it its own name, "The Newark Group". In fact, one of the grand divisions of time, the Triassic period, of the Mesozoic Era, in which the bed rocks of Millburn and the Watchung systems were founded, is often parenthetically called "Newark Time". The peculiar rock formations of this area, sandstone, shale, and traprock are found, naturally, in a few places elsewhere, but no where more clearly recognizable than here.

Time for the geologists is divided into six eras. The first era began untold millions of years ago, but the Newark Period was only between 35 and 45 millions of years ago, comparatively recently say the geologists, with all sorts of authenticated evidence around for knowing eyes to see. The year 1976 is part of the Post Glacial or Recent Era, which began almost yesterday in the longterm thinking of the scientists, but the hills of Millburn Township are very old with their flowing, rounded tops worn down by the forces of erosion through the ages.

New Jersey, 166 miles long by 57 miles wide at its widest portion, is part of the Atlantic Slope of North America. The Atlantic Slope is divided into two parts, the Appalachian Province, and the Coastal Plain. The boundary between the two provinces runs obliquely across the State from Trenton through New Brunswick to Raritan Bay. The easternmost division of the Appalachian Province is the Piedmont Plateau or Plain, which slopes gently southeastward from the base of the Appalachian Mountains to sea level at Newark. The first Watchung Mountains rise from the Plain, achieving their greatest height of 879 feet near Paterson, and their lowest of about 450 feet near Somerville. Millburn has its own "mountain", a tree-covered slope rising from its bed of traprock to a height of 550 feet. This upward thrusting pile of rock brings to an abrupt end the gentle hills which have meandered on their southwesterly journey from the Palisades of the Hudson River. In part of the short time occupied by recorded history, the summit of the escarpment which marks that Millburn terminal has been known affectionately, if somewhat incorrectly, historically speaking, as "Washington Rock", and now tamed and civilized, bears a lookout from which an expansive view may be had of the plains which lie beneath it extending to the towers of Manhattan twenty miles away.

Two miles southwest of Millburn, near Summit, the hills again move on their way. What great cataclysm of nature tore the gap in these traprock ridges is now only a matter of conjecture.

All of the State north of tie line drawn from Trenton to Newark Bay rests on solid bedrock with its covering of soil, varying from a few inches to many feet. In many hilly sections the bare rock appears at the surface.

It is not easy to realize that many of the materials forming the bedrock were brought in by the Gulf of Mexico, which in the Paleozoic Era flowed northward across the Continent, across Alabama, Tennessee, Virginia, Pennsylvania, New Jersey, and New England. To appreciate such a fact one must project himself back to a time when our shore line extended many miles farther east than it does now, and between us and the Atlantic Ocean on the northwest and southeast rose two other large land masses ?the lost lands of Appalachia and Acadia, the greater part of which has long since been drowned by the waters of the Atlantic, but during those long ago years played an important part in the history of our land. They bore the brunt of the attack by the elements, and from them was washed tremendous quantities of materials to build a new world.

It seems in reading the pages of Geology that nothing in those dim and far off days was ever done moderately. When it rained, it was a deluge; when the sun shone, it shone so fiercely that the land became a desert; when the seas came in they moved ruthlessly across the earth; and when the cold came, the ice sheets moved upon the land hundreds of feet thick.

The whole geology of New Jersey is the story of a constant battle between land and water. Repeatedly large portions of the State and sometimes the whole State were submerged beneath the sea. Then in another cycle, the land rose high above the water only to be engulfed in another era. Sometimes the land gained a little advantage in the huge masses of mud and sand and other sediment left by the water. In other times, the water carried away all the softer and lighter materials built up by former seas. The water cut deep channels and wide valleys as it swirled across the plain.

Probably Millburn lay buried beneath the sea during most of the early eras until the Fourth ? the Triassic period of the Mesozoic Era when the characteristic rock of this region was formed. Some widespread earth movement affected the eastern region, as a result of which the old lands of Appalachia and Acadia were broadly uplifted, and a series of basins formed between them. The Piedmont Region formed one basin. In the basin, sand, gravel, and mud, washed down from the higher regions of the northwest and southeast, began to accumulate. Some of the sediments, particularly their red color, so characteristic of New Jersey now, indicate a hot, dry, climate where torrential rains fell at intervals carrying debris with them. Fossil remains, found in great numbers, point to landlocked bays which rose and fell to various levels.

At last a time came when the basins were filled with sediment; the old lands to the southeast and northwest sank, never to rise again, and the waters disappeared.

The broad mud flats extended across the Piedmont Plain. Across these flats the giant reptiles, creatures of mud and slime, walked, leaving behind them forever imprinted, their many footprints, which are in some places nearby still perfectly preserved. Slabs measuring 1700 square feet from a quarry near Towaco in Morris County, show foot prints of 12 different species, and are now preserved in the Rutgers University Museum in New Brunswick. A restoration of the skeleton of a giant Hadrosaurus is mounted in the State Museum at Trenton.

The later period of deposit was also a time of great volcanic activity, and into the mass of drying mud, sand, and gravel volcanoes deep beneath the surface spewed their hot melted rock or lava, extruding it between the accumulated layers of mud and sand. In time, and under pressure, mud and sand become shale and sandstone, and the rapidly cooling lava, interbedded with those other materials, to form eventually thick sheets of shale, sandstone, and the dark blue or black basalt, known as traprock, which is found today in the quarries of this vicinity.

But the long days of creation were not completed. In that distant time, an ancient river, now thought to be the Hudson, diverted from its channel by a slow process of erosion, turned southeast across the buried Palisades ridge at Sparkhill, New York, and cut its raging course 475 feet below the present surface across New Jersey, and finally forced its way through a gap, the Hobart Gap, at Short Hills, to the sea. Later, during another cycle the river was diverted again, and forced to flow through its present channel. The only remnant of this ancient river found here now, is supposed to be Weequahic Lake in Newark, which finds its outlet the "Bound Creek" of the first settlers' deeds, through the meadows near Newark Airport to the bay.

In the Fifth, or Cenozoic Era, the great ice sheets moved down in three successive stages, pushing before them everything movable, filling depressions, digging valleys, and piling up for the people of Millburn Township, low mounds of accumulated gravel, rock, earth, stones, and other materials called generally "terminal moraine" which formed the short hills of the area. The southern extension of the ice is marked by a great mass of terminal moraine, which crosses the State in a curved line through Perth Amboy, Plainfield, Summit, Millburn, Morristown, Dover, Hackettstown and Belvidere. Sand, gravel, rock fragments, and boulders still mark the boundaries of the ice. Many large boulders left behind by the glacier may be found in the South Mountain Reservation today.

Temporary lakes were formed during the glacial epoch in several valleys. The largest of these lakes was Lake Passaic which occupied the entire Passaic River valley between the highlands on the north, Morristown on the west, Millburn on the east, and Moggy Hollow, near Bedminster to the south. The glacial drift closed the gap at Short Hills and other places, and as the air grew warmer and the ice began to melt, rivers which had drained through the gaps backed up and Lake Passaic came into being.

The lake was about 30 miles long, 8 to 10 miles wide, and was in places more than two hundred feet deep. Faint wavecut terraces and wavebuilt bars of waterworn gravel still mark the former shore line. When the ice front finally retreated enough, the Hobert Gap was closed forever with glacial drift, but a gap at Little Falls was laid bare, and the lake there was drained off and became extinct. The Great Swamp near New Vernon today is one of the few remaining evidences of Lake Passaic.

Dr. Henry Kummel, New Jersey State Geologist, writing in "A History of the City of Newark" by Frank Urquhart and others, says:

"The ice field, mighty sculptor that it was, wrought marvelous changes in its passage. It hewed and hacked, ploughed and gashed, tore and twisted, broke down and built up, until the whole surface of the earth was made over. It was rough treatment, but to it we owe the natural beauties of upper New Jersey today."

Many animals now extinct inhabited New Jersey during glacial and early postglacial times. Chief of these was the mastodon which probably followed the retreating ice northward. The remains of 19 individuals of the species have been reported in the State. Several were found between Hackettstown and Vienna; recently one was found near Stockholm; a good skeleton at Rutgers was recovered near Salem, a tooth almost two inches long was found near Belleville, and a portion of a skull was found near Westfield.

The hairy mammoth was also here, and the Greenland reindeer, the Arctic walrus, remains of the Canadian elk, two species of an extinct horse, an extinct moose, and a peccary have been found in New Jersey.

There is some evidence that man may have been here before the disappearance of the mastodon. At Trenton in glacial gravel, implements of chipped stone were found by Dr. Charles C. Abbott in 1875. These tools are much older than the tools of the modern Indian, the latter being found in soil layers much higher than the gravels. Traces of primitive man are found in many places in the world below the glacial drift, so that the findings at Trenton would seem to link New Jersey's very earliest inhabitants with his fellow creatures elsewhere.

Dr. Abbott, the principal authority of the Stone Age in New Jersey, in his report in 1877 to the Peabody museum of Harvard, wrote:

"There is much to be said of the theory that the Eskimoes of the north are the lineal descendants of the preglacial men whose implements are found in New Jersey and elsewhere."

William Nelson, in his "Indians of New Jersey" after quoting Dr. Abbott's report above mentioned, says:

"These tools found in the Trenton gravels are much more primitive than the implements of the people Columbus found here. Did they retreat with the glacier before the first white man had set foot on our shore? It may be that he has left unsuspected traces behind him, and that the expert will some day find in the Valley of the Passaic relics of that forgotten race."

Millburn lies in the Passaic Valley and perhaps someday beneath its deposits of terminal moraine discoveries may shed new light on the very earliest inhabitants.


Geology Bulletin #50, State of New Jersey (1950)
Dr. Henry B. Kummel and Dr. Volney Lewis
"The Stone Age in New Jersey" by Dr. Charles C. Abbott (1877)
"The Indians of New Jersey" by William Nelson (1894)
"History of the City of Newark" Urquhart and others (1913)