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Mere association with the remains of extinct animals is no longer considered a measure of an antiquity from the beginning, earlier than the peak of the last ice ages. The above relationships seem to be characteristic of the Lindenmeier site, discovered in 1934 and intensively investigated by Dr.

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 3

6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99

ACKNOWLEDGMENTS

GENERAL GEOLOGY OF THE LINDENMEIER SITE AND ADJACENT REGIONS

GENERAL STATEMENT

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 7 THE TERTIARY BEDS OF THE HIGH PLAINS

SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 CHARACTER OF THE COLORADO PIEDMONT

The northern tributaries of the Cache la Poudre-South Platte rivers have worked forward, capturing eastward flows and diverting them (eq. i). The upper tuff is massive, with almost no lamination or other evidence of depositional method.

NO. 2 ANTIQUITY OF LINDRNMEIER SITE BRYAN AND RAY 9 Overlving the Brule formation is the Arikaree, which consists of

SPRINGS AND THEIR SIGNIFICANCE

Both the springs and swampy areas are of great economic importance in this region, where most of the land is used for grazing purposes. The Lindenmeier site is almost surrounded by the winter range of the GreatWarren LivestockCo., whose sheep are lambed each spring on the green grass of the marshy meadows.

CLIMATE AND ITS INFLUENCE

In a flatter topography, however, the water is brought up to the surface by capillarity, and wide swampy meadows develop. 2 THE ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY II plains were removed by the early settlers and have not been able to.

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY II the plains was removed by the early settlers and has been unable to

THE CULTURE LAYER AND ITS LOCAL SETTING

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 13 merous bands of dark soil, similar to the soil now underlying the

THE LINDENMEIER VALLEY TOPOGRAPHY

This valley, as shown in Profile RS, Fig. 3, lay 50 to 60 feet above the present floor of the Lindenmeier Valley. We owe them the design features of the Lindenmeier valley and the preservation of the cultural layer.

NO. 2 ANTIQUITY OF LINDEN MEIER SITE BRYAN AND RAY 1/

During the period of occupation, as evidenced by excavations, the south slope of the valley and probably much of the valley floor. As the plain progressed northward through erosion of the dividing ridge, the hydraulic gradient between the valley and the plain became steeper. Ultimately, the groundwater was drained through one of the joints in the Brule.

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY I9 largely destroyed and persists only as a series of terrace remnants

CONCLUSION

PEDIMENTS AND TERRACES OF THE COLORADO PIEDMONT GENERAL STATEMENT

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 21 fluctuating climate, the effect of which on the grades of streams

SPOTTLEWOOD PEDIMENT

Over their cap of well-rounded stream gravel is a thin layer of wind-blown sand, which at its base has a layer of ventifacts.

COALBANK PEDIMENT

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 23 TIMNATH PEDIMENT

PIRACY BY THE SOUTH PLATTE RI\ER

THE CANYON-CUTTING CYCLE

ALLUVIAL TERRACES

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 25 The stages appear to have been short, and the minor tributaries were

A large part of the surface of the Kersey terrace is covered by dune sands and by alluvial fans, especially on the borders away from the rivers (pi. The Kersey stage of alluviation was followed by erosion and lowering of river levels to or below the present level. Between Kuner ter - race and the wide floodplain of the rivers, no lower terraces have been found.

MODERN FLOOD PLAIN

Its general surface lies between 25 and 30 feet above the present grade of the stream at the type locality. Pits of gravel and sand indicate that its composition is essentially the same as the older and higher Kersey Terrace. In some places the surface of the Kuner terrace rises as much as 20 feet above the level of the South Platte River.

NO. 2 ANTIQUITY OF LINDEN MEIER SITE — BRYAN AND RAY 27

SUMMARY

GLACIATION OF THE CACHE LA POUDRE VALLEY

28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 Peak, only 45 miles southwest of the Lindenmeier site and 25 miles

Their weathered condition and their topographical position above the valleys containing the younger glacial deposits testify to the relatively great age of this glacial phase. The locality is also well to the east of the most advanced position of the later glacial moraines, a fact which suggests a glaciation much larger than any formed in later times.

OTHER POSSIBLE PRE-WISCONSIN GLACIATIONS

Here a terminal moraine extends almost entirely across the valley, rising about 135 feet above the river level, which flows through a notch between the moraine and the rock of the northern valley wall (pi. 4).

HOME, AND A POSSIBLE EARLIER, GLACIAL SUBSTAGE

The clearest evidence for the pre-Dome glaciation period is the small side valleys, some 250 feet or more above the present level of the valley floor (C. and D in Fig. 8). It is possible that Atwood is using "pre-Wisconsin" in the lowan sense of the older terminology. Patches of striated and wind-polished rock occur on the plains above and on the upper parts of the walls of these small canyons.

CORRAL CREEK SUBSTAGE OF GLACIATION

That these surfaces have not yet been damaged by weathering is itself evidence of the relatively recent dating of the Home subphase, which is considered to date from Wisconsin II. This tongue extended into the Cache la Poudre River drainage, where a moraine complex was built that now dams the valley and holds the water of Chambers Lake. This cash register is so fresh that it stands in stark contrast to the heavily weathered cash register of the Prairie Divide stage.

LONG DRAW SUBSTAGE OF GLACIATION

The mass of ice moving down JoeWright Creek (Home Quadrangle) was larger than those in the other valleys, for it was fed from a larger accumulation area below Medicine Bow's high peaks. Recently, an artificial dam has been built on one of these retreating moraines to raise the water level of the natural lake. The difference in the amount of weathering of the moraine, the distinct topographic location of the moraines in the valleys, and the widespread distribution of comparable moraines lead to the conclusion that these features indicate a glacial substage that is separate and distinct from the home. substep.

PROTALUS SUBSTAGE

TERRACES OF THE CACHE LA POUDRE CANYON THE CANYON

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 37

99Smaller but well-developed cones occur in the Lesser Glacial portion, but well-developed cones occur in the glacial portion of the canyon, indicating the rapidity with which some of the Precambrian and shale bedrock was broken up. Much of the talus material consists of fine sand and crushed rock, products of local weathering and frost action.

NATURE OF VALLEY TRAINS

NO. 2 ANTIQUITY OK LINDENMEIER SITE BRYAN AND RAY 39 METHODS OF TERRACE STUDY

40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99

Many terraces have been so eroded that their remains show no trace of the original surface. Profiles of the terraces show that there is a general tendency for the terrace remnants to converge towards the mouth of the gorge. The original relationship between the terraces of Cache la Poudre Canyon was worked out on a large map on which the profile of the river.

42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 was plotted with a horizontal scale of 2 inches to the mile, and the

TERRACE NO. 6

TERRACE NO. 5

TERRACE NO. \

TERRACE NO. 3

46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 that a genetic relationship with the Long Draw moraines is not only

TERRACE NO. 2

TERRACE NO. I

NO. 2 ANTIQUITY OF LINDENMEIER SITE BRYAN AND RAY 47 of the mountain front, these low terraces are indistinguishal)le and

CORRELATION OF THE TERRACES OF THE CACHE LA POUDRE CANYON WITH THOSE OF THE COLORADO PIEDMONT

48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 correlation may be made between tbe glacial substages of the mountain

All three locations were occupied after the construction of the upper surface of the terrace and before its subdivision. At Kersey, the artifacts do not occur on the terrace, but rather slightly above terrace level in dune sands. It is likely that the river periodically washed away the foot of the slope and moved from time to time, leaving a barren bed.

GLACIATION AS A CHRONOLOGY

The sand is wind-blown and rises as a dune on a gentle slope from the level of the Kersey terrace to a height of about 30 feet (pi. 3, fig. i). However, since the artifacts are similar to those found at the Lindenmeier site, it appears that they are contemporaneous and that the Folsom hunters camped on a dune that was blown from the river's floodplain when the river flowed at the level of the Kersey- the terrace. The Dent and Kersey sites confirm the connection between the culture layer in the small valley at Lindenmeier and Kersey.

50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 of knowledge, it is necessary to relate the glacial substages in the

THE EUROPEAN GLACIAL CHRONOLOGY

THE MAJOR ICE ADVANCES

However, there is a growing tendency to consider that each of the glacial stages was multiple and consisted of at least two. This view is supported by many new field facts concerning the terrace systems, loess and pollen-bearing beds of the periglacial region of southern Germany. The recognition of weathering zones as evidence of the milder climates of interglacial or interstadial periods has been of great importance.

52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 before the complexities of the advance and the final retreat of the

LATE-GLACIAL CHRONOLOGY

If, after the recent Lowan decision (Kay, 1931, and Leighton, 1931), the Warthe is considered an early stage of the last glaciation, this may well happen. However, this placement of the Lowan as the first Wisconsin advance in North America is not universally accepted by American geologists (Leverett, 1939, and Lugn, 1935). The Brandenburg moraine, or Weichsel substage, is generally thought to represent the culmination of the last glaciation, except by De Geer.

54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99

This is likely to be an oversimplification and our ignorance of the facts prevents it. 12.-Subdivisions of the late glacial period, with diagrammatic representations of some advances and retreats of the ice. For some geologists, this marks the end of the Ice Age, a view put forward by Gams (1938), whose classification is shown in Figure 12 left.

56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 Figures ii and 12 show that this interval is divided into the Dani-

The Scandinavian moraine of Antevs is not clearly described by De Geer, but the Scandinavian moraine of Antev is not clearly described by De Geer, but Antevs (1928, p. 160) estimates that this period is 2000 years. plus the 670 years it took to build the moraine defined by Sauramo in Finland. Sauramo (1928) states that he counted 2,400 varves in southern Finland, which together with the time interval of 670 years for the moraine would give more than 3,000 years for the length of the Gothi Glacial – a figure accepted by many authors. This interval includes the period during which the ice retreats from the moraine to its division at Ragunda.

GEOCHRONOLOGY IN NORTH AMERICA METHODS AND RESULTS

EXPLANATION

In the New Haven area the top of the clay beds has always been eroded and the base is largely unknown. At a later period the upper part of the bottom zone was entrained and warped in a climate of Arctic severity. Based on this evidence, it appears that the red clay in the Berlin area is older than the last interglacial, or interstadial, and may belong to an earlier glacial advance.

62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 Vineyard lack true morainic topography and are formed of sand and

The intervals x and 3; are estimated by applying the velocities of the following intervals, giving 9,000 and 1,200 years, respectively. The interval 2, or 1,500 miles, is arbitrarily given a rate of retreat half that of the previous interval, thus yielding i,ooo-f years. However, a time interval n remains, from the last disappearance of the ice in Labrador to the present.

64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 99 plained in part on his pages i8 and 19, where detailed studies of the

Also Antevs' (1931) new estimate of 10,000 years for the two intervals St. Johnsbury-Stony Lake and Stony Lake-Mattawa. If the same approach is then used for the retreat from the Harbor Hill moraine, the interval is 2000 years.

VALIDITY OF RESULTS

The given numbers are only first approximations, which can be considered to be the correct order of magnitude with a certain degree of reliability. The error in estimating the length of the postglacial substage is probably small and. In addition, the length of the diglacial is not controlled by counting varves and is a pure estimate.

FOLSOM CULTURE OF LATE-GLACIAL AGE SUMMARY OF EVIDENCE

2 THE ANTIQUITY OF LINDF.N IMRIER SITE — BRYAN AND RAY 69 and therefore the late stage of the moraine is the time represented by the terrace. It is without much question about the right order of magnitude and must be at most 25 percent too large, or on the other hand more than 30 percent too small. Since the camps and relics of Folsom man are found on the finished surface of the terraces or in the upper gravel, the culture should be younger rather than older than the climax of this glacial subphase.

EVIDENCE FROM OTHER FOLSOM SITES

Present writers place the peak of Wisconsin at the time of the Home-Tazewell-Cary-New York-Brandenburg substage, about 35,000+ years ago. None of these deposits offer any current assistance in the problem of definitively relating the Folsom culture to a dateable geologic horizon. In addition, the terraces of the Colorado Piedmont can be traced in the future in ice-related sediments of eastern Nebraska.

GEOGRAPHY OF THE FOLSOM CULTURE

BIBLIOGRAPHY

The continued detailed efforts of the Nebraska geologists promise to provide a solution to this difficult and complicated problem. Recent deposits of Chaco Canyon, New Mexico, in relation to the life of the prehistoric peoples of Pueblo Bonito (abstr.). The tents of the Smithsonian Institution Expedition are on the level of the old valley floor.