3) is fine-grained, moderately sorted and in particular composed of
subangular, exceptionally to angular quartz grains (about 75 % of rock volume) with a low degree of sphericity and [M.sub.d] 0.22 mm.
Wustenquartz grains are
subangular to subrounded, 50-100 [micro]m in diameter and identified by the amorphous iron coatings on the surface and fracture faces (Fig.
Nas coberturas argilo-siltosas, em diferentes dominios de encosta, verifica-se a presenca de pequenos graos de quartzo remanescentes (alem de alguma muscovita) cujo arranjo geometrico
subangular a subarredondado indica pelo menos dois ciclos de transporte e deposicao.
spondiadis differ from the other 2 known Mexican species in the completely black head and pronotum, the lack of genal processes, and the apically
subangular forewings.
Pronotum slightly widening from anterior to posterior margin; anterior margin subtruncate, very slightly concave in middle, posterior margin broadly rounded; disc flat with a faint medial carina in posterior area, lateral margins straight and
subangular (Fig.
The primary component of Unit I was medium grained (1.5-2 [phi]),
subangular to subrounded, poorly sorted, quartz-rich sand and
subangular to subrounded 5-25 cm thick cobbles.
Aiolopus strepens is a species of medium size, 18 to 20 mm in males and 21-28 mm in females, with a pronotum with a
subangular posterior edge.
Microfacies: A bimodal, very poorly sorted, packstone-grainstone assemblage of abundant very coarse to pebble sized, subrounded to
subangular clasts (same two microfacies as facies 1 clasts) and coarse peloids, which are found within a finer, medium to fine sand grade matrix of deformed radialfibrous ooids, micritic ooids (with a tangential fabric recognisable in peripheral parts) and aggregate grains.
The basal sandstone unit is quartzose, very pale orange, very fine to fine grained,
subangular to subrounded, and at least 35 m (115 ft) thick; but known only in the subsurface in northwestern Wisconsin (Mudrey and others, 1987).
A mixture of very compact, fine-grained, grey-brown, sandy silt with
subangular to subrounded striated pebbles and cobbles of mixed lithologies was recovered from the lower 64-60 m overlying bedrock.