N2 — outside your level filter

it can reasonably be concluded that; is to be regarded as

この地層ちそうは約やく一万年前いちまんねんまえに形成けいせいされたと考かんがえられる。

kono chisou wa yaku ichimannenmae ni keisei sareta to kangaerareru.

This stratum can reasonably be taken to have formed about ten thousand years ago. neutral

かつてこの病気びょうきは遺伝いでんによるものと考かんがえられていたが、現在げんざいでは否定ひていされている。

katsute kono byouki wa iden ni yoru mono to kangaerarete ita ga, genzai de wa hitei sarete iru.

This illness was once held to be hereditary, but that view has since been rejected. neutral

Variants

と考えられているtokangaerareteirualternant
the ている form reports a view already SETTLED in the field ("is held to be") rather than the conclusion this writer is drawing — the difference between citing a consensus and reaching one, at the same academic register.

This pattern, conjugated

とかんがえられるto kangaerareruN2formal