[5] Remnants of sandstone still clinging to the conglomerate roof eventually fell to the floor, forming an archaeologically sterile layer that separated later human occupation periods.

[5] A refuse soft clay soil varying in thickness from 3 to 9 in (7.6 to 22.9 cm) composes the oldest occupation level at the site.

[7] Junius Bird notes in Travels and Archaeology in South Chile that this layer contained significantly more sediment in relation to artifact distribution.

[7] In the Late Pleistocene, prior to 12,500 years BP, the area surrounding Cueva Fell was dominated by high winds, year-round freezing temperatures, and annual precipitation under 300 mm.

In what has been described as a possible South American equivalent to the Younger Dryas, the Patagonian region experienced a period of low temperatures and high precipitation as well as advancing glaciers.

While this produced significant changes in some taxa, humans, at this time, were already becoming adept at adjusting to new environments and appear not to have been deleteriously affected by the changeable and unpredictable climate.

[17][18] The period of 9,000 to 6,000 years BP saw less remarkable shifts in climate, with a general trend away from xeric taxa and, it is then presumed, an increase in precipitation.

There is insufficient radiocarbon control at the site to determine local climate conditions post-6,000 years BP, however regional ecology suggests a slight shift towards more aridity.

The area receives less than 400 mm (16 in) annual precipitation (typical for the Patagonia region but much drier than neighbouring coastal or mountain terrains) and is dominated by bunch grasses from the genera Festuca and Stipa, along with a variety of herbaceous vegetation.

Bone remains of the horse, llama and ground sloth all display puncture marks, most likely made by the Patagonia panther.

Analysis of pollen extracted from Cueva Fell suggested a substantial reduction in grassland in southern Patagonia in the period just preceding these extinctions, and was an early piece of evidence in the mounting argument against hunting as the primary cause of species collapse.

[24] Analysis of canine remains found in all five human occupation levels of the cave initially suggested they were those of domestic dog (Canis familiaris).

Bird notes in a 1970 journal article that "stone artefacts shaped by pecking and grinding are so generally absent among Paleo-Indian finds that exceptions are noteworthy".

This theory basically holds that the Clovis culture constituted the earliest peoples to arrive in and inhabit North America.

At the time the theory was proposed no archaeological evidence had been discovered in the Americas which pre-dated 11,050 to 10,800 years BP, or the onset of the Clovis culture.

[34] Based on the current understanding of archaeological evidence, it is now widely accepted that a pre-Clovis culture colonized the Americas via a Pacific coastal route sometime between 14,000 and 12,000 years BP.

Many researchers now agree that occupation of Tierra del Fuego, between 11,000 and 10,500 years ago, simply does not provide enough time for mid-continental migration.

A similar argument is made about Monte Verde, which may be the best known and most widely accepted of these sites and which pre-dates Clovis by approximately 1,000 years.

[36] Other Late Pleistocene sites in Argentina, such as Cerro Tres Tetas, Cueva Casa del Minero and Piedra Museo are also contemporaneous with Clovis and the early occupation at Fell's Cave.

The fishtail points of Cueva Fell thus represent crucial evidence in the distinction between tool technologies in the southern and northern continents of the Americas.

Finally, Cueva Fell deserves recognition for representing possibly the earliest occupation of Fuego-Patagonia approximately 11,000 BP.

The early inhabitants of Fuego-Patagonia signify sparse populations spread out over large territories and chances of site discovery in this region are low.

[40] Compounding the low likelihood of site discovery in this region is the deeply buried contexts associated with such early occupation and the subsequent increase of various perturbation processes threatening the archaeological integrity.

[40] Low population density combined with these other factors make Junius Bird's discovery of Cueva Fell in 1936 truly remarkable in and of itself.