Locality
Arctic Slope of Alaska locality USGS 11606, north of Maybe Creek. This locality is a bluff approximately 10 m high on the east side of an unnamed tributary of the Price River. The predominant lithologies are bentonitic clays overlying a silty sandstone capped by coal beds up to 2 m thick, which are in turn overlain by a white-gray medium-grained sandstone. Irregularly dispersed throughout the clay are nodules and sheets of ferruginous limestone (sideritic) which, although light gray when fresh, weather to a rusty brown. With the exception of some poorly preserved plant matter in the upper sandstones, and impressions of platanoid leaves in the power sandtsones, the plant material is confined to these fine-grained iron-rich nodules and is preserved as impressions totally lacking cuticle. There is little evidence of post-mortem decay but many leaves are penetrated by vertical fossil rootlets. Platanoid leaves are most common in siltier/sandier facies. The uppermost coal surface supports several in situ tree bases each of which is approximately 20 cm in diameter.
Latitude: 69.528329 °N
Longitude: -153.887128 °W
Description
Leaf: simple; asymmetrical (?); elliptic (?); apex missing; base asymmetrically decurrent; margin entire; venation pinnate, brochidodromous; midvein moderate, uniformly curved; secondary veins moderate, arising at an angle of 40-55° with no significant change along the length of the midvein; secondaries near the base initially slightly recurved then becoming curved near margin; more apical secondaries straight then curved near margin; all secondary veins forming arches and joining the superadjacent secondary at varying angles from acute to obtuse; simple intersecondary veins present; tertiary veins weak, transverse, percurrent or connecting with intersecondary veins, more or less straight, predominantly forming obtuse angles with admedial sides of the secondaries and acute angles with abmedial sides of secondaries, but sometimes approximately 90° in both cases; third and fourth order loops present at the margin; fine venation invisible in this specimen.
Remarks
This leaf is undoubtedly of the magnoliidean type but without the apex it is difficult to say how this specimen relates to other leaves of similar age.