The uppermost 15 m is a sequence alternating between laminated, stromatolitic calcisiltite, and calcilutite and calcisiltite that are argillaceous and fossiliferous.
32.
The Bogot?Formation, named after the capital, is a Paleocene to Lower Eocene argillaceous unit concordantly overlying the lower Paleogene sequence.
33.
Similarly, " argillaceous sandstones " are sandstones consisting primarily of quartz grains, with the interstitial spaces filled with clay minerals.
34.
The strata of this member consist mainly of interbedded fine grained, slope-forming, argillaceous sandstone and sandy argillite, and subordinate claystone.
35.
The forewings of the males are ocherous to argillaceous shaded with brown, with a large, dorsal area of black scales at the inner angle.
36.
The forewings are pale argillaceous greyish, with brownish fuscous spots and some sprinkling of brownish fuscous, especially along the dorsum and above the tornus.
37.
The geological structure of the deposit can be compared with a " layer cake " : argillaceous deposits are interleaved by limestone, which makes drilling difficult.
38.
The formation throughout its geographic range consists of layer upon layer of well-bedded argillaceous silty to sandy shales, with smaller interbeds of arkosic sandstone.
39.
The base of the Tunbridge Wells Sand is marked by a distinct change from the predominantly argillaceous sediments of the Wadhurst Clay to siltstones and silty sands.
40.
It is composed of greenish shale with alternating interbedded greenish argillaceous platy siltstone beds and lenticular ( some cm thick ) fine-grained sandstone and siltstone.
