Specimens of Archaeopteryx The end of the feather has an obtuse angle of 110°, while the barbs branch off from the rachis at an angle of around 25°. The barbs branch noticeably into barbules, as in the feathers of modern birds. The base of the feather consists of plumulaceous barbs which are unconnected to one another and result in a down-like appearance. This tuft of down led Griffiths to conclude that "Archaeopteryx" might have been endothermic in that it implies the use of thermal insulation. The feather is clearly asymmetrical, which has been interpreted by many scientists to be a clear indication of
Calamus Creek (Wisconsin) with drumlins and scattered muck deposits. Soils are predominantly well drained silt over calcareous sandy loam till." The original vegetation cover is primarily white oak, black oak, bur oak, marsh and sedge meadow, wet prairie, and lowland shrubs. Calamus Creek is part of the larger Upper Rock River Basin. The of the streams comprising the Calamus Creek watershed cover , or 19315 acres, with 54.39 acres covered by five unnamed lakes and 3627.39 acres of wetlands. The watershed includes extensive wetlands, some of which are in the process of restoration. Parts of Calamus Creek are designated wadable nursery waters for