▁gla u con it ic ▁s ilt - s and stone ▁occasionally ▁bearing ▁extremely ▁ac rit arch - rich ▁ph osph atic ▁p eb bles ; ▁gradually ▁transition ing ▁up wards ▁into ▁the ▁upper , ▁the ▁ 3   m ▁thick ▁Ris pe b jer g ▁Member , ▁a ▁sand stone . ▁ ▁References ▁ ▁Category : Ge ology ▁of ▁Den mark ▁Category : C amb rian ▁System ▁of ▁Europe ▁Category : B orn holm <0x0A> </s> ▁e Not es ▁is ▁a ▁student ▁and ▁teacher ▁educational ▁website ▁founded ▁in ▁ 1 9 9 8 ▁by ▁Brad ▁S ator is ▁and ▁Alexander ▁Blo oming dale , ▁that ▁provides ▁material ▁to ▁help ▁students ▁complete ▁home work ▁assign ments ▁and ▁study ▁for ▁ex ams . ▁ ▁Based ▁in ▁Seattle , ▁Washington ▁in ▁the ▁United ▁States , ▁e Not es ▁special izes ▁in ▁less on ▁plans , ▁study ▁gu ides ▁and ▁literary ▁critic isms . ▁It ▁also ▁hosts ▁an ▁active ▁home work ▁help ▁portal ▁where ▁students ▁can ▁ask ▁educ ators ▁academic ▁questions . ▁The ▁Home work ▁Help ▁section ▁has ▁hundreds ▁of ▁thousands ▁of ▁questions ▁with ▁answers . ▁ ▁The ▁website ' s ▁material ▁mainly ▁focus es ▁on ▁literature ▁and ▁history , ▁though ▁the ▁company ▁offers ▁a ▁variety ▁of ▁different ▁topics ▁within ▁the ▁human ities . ▁A ▁network ▁of ▁over ▁ 1 , 0 0 0 ▁teachers ▁and ▁profess ors ▁cont ributes ▁much ▁of ▁the ▁content . ▁It ▁is ▁different ▁from ▁other ▁online ▁subscription ▁education ▁services ▁in ▁that ▁an ▁in - house ▁publishing ▁team ▁ed its ▁uploaded ▁works